diff --git a/src/core/rendering/Renderer.ts b/src/core/rendering/Renderer.ts
index 8de5c888..83ece4f2 100644
--- a/src/core/rendering/Renderer.ts
+++ b/src/core/rendering/Renderer.ts
@@ -72,10 +72,10 @@ export abstract class Renderer implements Disposable {
         this.schedule_render();
     }
 
-    pointer_pos_to_device_coords(v: Vector2): Vector2 {
+    pointer_pos_to_device_coords(e: MouseEvent): Vector2 {
         const coords = this.renderer.getSize(new Vector2());
-        coords.width = (v.x / coords.width) * 2 - 1;
-        coords.height = (v.y / coords.height) * -2 + 1;
+        coords.width = (e.offsetX / coords.width) * 2 - 1;
+        coords.height = (e.offsetY / coords.height) * -2 + 1;
         return coords;
     }
 
diff --git a/src/quest_editor/gui/EntityListView.ts b/src/quest_editor/gui/EntityListView.ts
index bb74fec6..a34f6253 100644
--- a/src/quest_editor/gui/EntityListView.ts
+++ b/src/quest_editor/gui/EntityListView.ts
@@ -3,8 +3,7 @@ import { bind_children_to, el } from "../../core/gui/dom";
 import "./EntityListView.css";
 import { entity_data, EntityType } from "../../core/data_formats/parsing/quest/entities";
 import { ListProperty } from "../../core/observable/property/list/ListProperty";
-import { Vec2 } from "../../core/data_formats/vector";
-import { Disposable } from "../../core/observable/Disposable";
+import { entity_dnd_source } from "./entity_dnd";
 
 export abstract class EntityListView<T extends EntityType> extends ResizableWidget {
     readonly element: HTMLElement;
@@ -19,7 +18,7 @@ export abstract class EntityListView<T extends EntityType> extends ResizableWidg
         this.disposables(
             bind_children_to(list_element, entities, this.create_entity_element),
 
-            make_draggable(list_element, target => {
+            entity_dnd_source(list_element, target => {
                 if (target !== list_element) {
                     const drag_element = target.cloneNode(true) as HTMLElement;
                     drag_element.style.width = "100px";
@@ -43,119 +42,3 @@ export abstract class EntityListView<T extends EntityType> extends ResizableWidg
         return div;
     };
 }
-
-export type EntityDrag = {
-    readonly offset_x: number;
-    readonly offset_y: number;
-    readonly data_transfer: DataTransfer;
-    readonly drag_element: HTMLElement;
-    readonly entity_type: EntityType;
-};
-
-function make_draggable(
-    element: HTMLElement,
-    start: (target: HTMLElement) => [HTMLElement, any] | undefined,
-): Disposable {
-    let detail: { drag_element: HTMLElement; entity_type: EntityType } | undefined;
-    const grab_point = new Vec2(0, 0);
-
-    function clear(): void {
-        if (detail) {
-            detail.drag_element.remove();
-            detail = undefined;
-        }
-    }
-
-    function redispatch(e: DragEvent): void {
-        if (e.target instanceof HTMLElement && detail && e.dataTransfer) {
-            e.target.dispatchEvent(
-                new CustomEvent<EntityDrag>(`phantasmal-${e.type}`, {
-                    detail: {
-                        ...detail,
-                        data_transfer: e.dataTransfer,
-                        offset_x: e.offsetX,
-                        offset_y: e.offsetY,
-                    },
-                    bubbles: true,
-                }),
-            );
-        }
-    }
-
-    function dragstart(e: DragEvent): void {
-        if (e.target instanceof HTMLElement) {
-            clear();
-
-            const result = start(e.target);
-
-            if (result) {
-                grab_point.set(e.offsetX + 2, e.offsetY + 2);
-
-                detail = {
-                    drag_element: result[0],
-                    entity_type: result[1],
-                };
-
-                detail.drag_element.style.position = "fixed";
-                detail.drag_element.style.pointerEvents = "none";
-                detail.drag_element.style.zIndex = "500";
-                detail.drag_element.style.top = "0";
-                detail.drag_element.style.left = "0";
-                detail.drag_element.style.transform = `translate(${e.clientX -
-                    grab_point.x}px, ${e.clientY - grab_point.y}px)`;
-                document.body.append(detail.drag_element);
-
-                e.dataTransfer!.setDragImage(el.div(), 0, 0);
-            }
-        }
-    }
-
-    function dragenter(e: DragEvent): void {
-        redispatch(e);
-    }
-
-    function dragover(e: DragEvent): void {
-        if (e.target instanceof HTMLElement && detail) {
-            detail.drag_element.style.transform = `translate(${e.clientX -
-                grab_point.x}px, ${e.clientY - grab_point.y}px)`;
-
-            redispatch(e);
-        }
-    }
-
-    function dragleave(e: DragEvent): void {
-        redispatch(e);
-    }
-
-    function dragend(): void {
-        clear();
-    }
-
-    function drop(e: DragEvent): void {
-        try {
-            redispatch(e);
-        } finally {
-            clear();
-        }
-    }
-
-    element.addEventListener("dragstart", dragstart);
-    document.addEventListener("dragenter", dragenter);
-    document.addEventListener("dragover", dragover);
-    document.addEventListener("dragleave", dragleave);
-    document.addEventListener("dragend", dragend);
-    document.addEventListener("drop", drop);
-
-    return {
-        dispose(): void {
-            element.removeEventListener("dragstart", dragstart);
-            document.removeEventListener("dragenter", dragenter);
-            document.removeEventListener("dragover", dragover);
-            document.removeEventListener("dragleave", dragleave);
-            document.removeEventListener("dragend", dragend);
-            document.removeEventListener("drop", drop);
-
-            clear();
-        },
-    };
-}
diff --git a/src/quest_editor/gui/entity_dnd.ts b/src/quest_editor/gui/entity_dnd.ts
new file mode 100644
index 00000000..0964e342
--- /dev/null
+++ b/src/quest_editor/gui/entity_dnd.ts
@@ -0,0 +1,120 @@
+import { entity_data, EntityType } from "../../core/data_formats/parsing/quest/entities";
+import { Disposable } from "../../core/observable/Disposable";
+import { Vec2 } from "../../core/data_formats/vector";
+import { el } from "../../core/gui/dom";
+
+export type EntityDragEvent = {
+    readonly entity_type: EntityType;
+    readonly drag_element: HTMLElement;
+    readonly event: DragEvent;
+};
+
+let dragging_details: Omit<EntityDragEvent, "event"> | undefined = undefined;
+const listeners: Map<(e: EntityDragEvent) => void, (e: DragEvent) => void> = new Map();
+const grab_point = new Vec2(0, 0);
+let drag_sources = 0;
+
+export function add_entity_dnd_listener(
+    element: HTMLElement,
+    type: "dragenter" | "dragover" | "dragleave" | "drop",
+    listener: (event: EntityDragEvent) => void,
+): void {
+    function event_listener(event: DragEvent): void {
+        if (dragging_details) {
+            listener({ ...dragging_details, event });
+        }
+    }
+
+    listeners.set(listener, event_listener);
+    element.addEventListener(type, event_listener);
+}
+
+export function remove_entity_dnd_listener(
+    element: HTMLElement,
+    type: "dragenter" | "dragover" | "dragleave" | "drop",
+    listener: (event: EntityDragEvent) => void,
+): void {
+    const event_listener = listeners.get(listener);
+
+    if (event_listener) {
+        listeners.delete(listener);
+        element.removeEventListener(type, event_listener);
+    }
+}
+
+export function entity_dnd_source(
+    element: HTMLElement,
+    start: (target: HTMLElement) => [HTMLElement, EntityType] | undefined,
+): Disposable {
+    function dragstart(e: DragEvent): void {
+        if (e.target instanceof HTMLElement) {
+            const result = start(e.target);
+
+            if (result) {
+                grab_point.set(e.offsetX + 2, e.offsetY + 2);
+
+                dragging_details = {
+                    drag_element: result[0],
+                    entity_type: result[1],
+                };
+
+                dragging_details.drag_element.style.position = "fixed";
+                dragging_details.drag_element.style.pointerEvents = "none";
+                dragging_details.drag_element.style.zIndex = "500";
+                dragging_details.drag_element.style.top = "0";
+                dragging_details.drag_element.style.left = "0";
+                dragging_details.drag_element.style.transform = `translate(${e.clientX -
+                    grab_point.x}px, ${e.clientY - grab_point.y}px)`;
+                document.body.append(dragging_details.drag_element);
+
+                if (e.dataTransfer) {
+                    e.dataTransfer.effectAllowed = "copy";
+                    e.dataTransfer.setDragImage(el.div(), 0, 0);
+                    // setData is necessary for FireFox.
+                    e.dataTransfer.setData(
+                        "phantasmal-entity",
+                        entity_data(dragging_details.entity_type).name,
+                    );
+                }
+            }
+        }
+    }
+
+    element.addEventListener("dragstart", dragstart);
+
+    if (++drag_sources === 1) {
+        document.addEventListener("dragover", dragover);
+        document.addEventListener("dragend", dragend);
+    }
+
+    return {
+        dispose(): void {
+            element.removeEventListener("dragstart", dragstart);
+
+            if (--drag_sources === 0) {
+                document.removeEventListener("dragover", dragover);
+                document.removeEventListener("dragend", dragend);
+            }
+        },
+    };
+}
+
+function dragover(e: DragEvent): void {
+    e.preventDefault();
+
+    if (e.dataTransfer) {
+        e.dataTransfer.dropEffect = "none";
+    }
+
+    if (dragging_details) {
+        dragging_details.drag_element.style.transform = `translate(${e.clientX -
+            grab_point.x}px, ${e.clientY - grab_point.y}px)`;
+    }
+}
+
+function dragend(): void {
+    if (dragging_details) {
+        dragging_details.drag_element.remove();
+        dragging_details = undefined;
+    }
+}
diff --git a/src/quest_editor/rendering/QuestEntityControls.ts b/src/quest_editor/rendering/QuestEntityControls.ts
index fb32d0c6..f77ae267 100644
--- a/src/quest_editor/rendering/QuestEntityControls.ts
+++ b/src/quest_editor/rendering/QuestEntityControls.ts
@@ -9,9 +9,13 @@ import { AreaUserData } from "./conversion/areas";
 import { SectionModel } from "../model/SectionModel";
 import { Disposable } from "../../core/observable/Disposable";
 import { Disposer } from "../../core/observable/Disposer";
-import { EntityDrag } from "../gui/EntityListView";
 import { is_npc_type } from "../../core/data_formats/parsing/quest/entities";
 import { npc_data } from "../../core/data_formats/parsing/quest/npc_types";
+import {
+    add_entity_dnd_listener,
+    EntityDragEvent,
+    remove_entity_dnd_listener,
+} from "../gui/entity_dnd";
 
 const DOWN_VECTOR = new Vector3(0, -1, 0);
 
@@ -20,11 +24,13 @@ type Highlighted = {
     mesh: Mesh;
 };
 
+enum PickMode {
+    Creating,
+    Transforming,
+}
+
 type Pick = {
-    /**
-     * Whether we picked an entity that is being created or one that has existed before.
-     */
-    creating: boolean;
+    mode: PickMode;
 
     initial_section?: SectionModel;
 
@@ -82,12 +88,20 @@ export class QuestEntityControls implements Disposable {
         renderer.dom_element.addEventListener("mousedown", this.mousedown);
         renderer.dom_element.addEventListener("mousemove", this.mousemove);
         renderer.dom_element.addEventListener("mouseup", this.mouseup);
-        renderer.dom_element.addEventListener("phantasmal-dragenter", this.dragenter);
-        renderer.dom_element.addEventListener("phantasmal-dragover", this.dragover);
-        renderer.dom_element.addEventListener("phantasmal-dragleave", this.dragleave);
+        add_entity_dnd_listener(renderer.dom_element, "dragenter", this.dragenter);
+        add_entity_dnd_listener(renderer.dom_element, "dragover", this.dragover);
+        add_entity_dnd_listener(renderer.dom_element, "dragleave", this.dragleave);
+        add_entity_dnd_listener(renderer.dom_element, "drop", this.drop);
     }
 
     dispose(): void {
+        this.renderer.dom_element.removeEventListener("mousedown", this.mousedown);
+        this.renderer.dom_element.removeEventListener("mousemove", this.mousemove);
+        this.renderer.dom_element.removeEventListener("mouseup", this.mouseup);
+        remove_entity_dnd_listener(this.renderer.dom_element, "dragenter", this.dragenter);
+        remove_entity_dnd_listener(this.renderer.dom_element, "dragover", this.dragover);
+        remove_entity_dnd_listener(this.renderer.dom_element, "dragleave", this.dragleave);
+        remove_entity_dnd_listener(this.renderer.dom_element, "drop", this.drop);
         this.disposer.dispose();
     }
 
@@ -112,9 +126,7 @@ export class QuestEntityControls implements Disposable {
         this.process_event(e);
         this.stop_transforming();
 
-        const new_pick = this.pick_entity(
-            this.renderer.pointer_pos_to_device_coords(new Vector2(e.offsetX, e.offsetY)),
-        );
+        const new_pick = this.pick_entity(this.renderer.pointer_pos_to_device_coords(e));
 
         if (new_pick) {
             // Disable camera controls while the user is transforming an entity.
@@ -132,9 +144,7 @@ export class QuestEntityControls implements Disposable {
     private mousemove = (e: MouseEvent) => {
         this.process_event(e);
 
-        const pointer_device_pos = this.renderer.pointer_pos_to_device_coords(
-            new Vector2(e.offsetX, e.offsetY),
-        );
+        const pointer_device_pos = this.renderer.pointer_pos_to_device_coords(e);
 
         if (this.selected && this.pick) {
             if (this.moved_since_last_mouse_down) {
@@ -177,16 +187,11 @@ export class QuestEntityControls implements Disposable {
         this.renderer.schedule_render();
     };
 
-    private dragenter = (e: Event) => {
+    private dragenter = (e: EntityDragEvent) => {
         const area = quest_editor_store.current_area.val;
         if (!area) return;
 
-        const detail = (e as CustomEvent<EntityDrag>).detail;
-
-        const pointer_position = this.renderer.pointer_pos_to_device_coords(
-            new Vector2(detail.offset_x, detail.offset_y),
-        );
-
+        const pointer_position = this.renderer.pointer_pos_to_device_coords(e.event);
         const { intersection, section } = this.pick_terrain(pointer_position, new Vector3());
 
         let position: Vec3 | undefined;
@@ -208,15 +213,18 @@ export class QuestEntityControls implements Disposable {
         const quest = quest_editor_store.current_quest.val;
 
         if (quest && position) {
-            if (is_npc_type(detail.entity_type)) {
-                const data = npc_data(detail.entity_type);
+            if (is_npc_type(e.entity_type)) {
+                const data = npc_data(e.entity_type);
 
-                if (data.pso_type_id !== undefined && data.pso_roaming != undefined) {
-                    detail.drag_element.style.display = "none";
-                    detail.data_transfer.dropEffect = "copy";
+                if (data.pso_type_id != undefined && data.pso_roaming != undefined) {
+                    e.drag_element.style.display = "none";
+
+                    if (e.event.dataTransfer) {
+                        e.event.dataTransfer.dropEffect = "copy";
+                    }
 
                     const npc = new QuestNpcModel(
-                        detail.entity_type,
+                        e.entity_type,
                         data.pso_type_id,
                         0,
                         0,
@@ -235,7 +243,7 @@ export class QuestEntityControls implements Disposable {
                     quest_editor_store.set_selected_entity(npc);
 
                     this.pick = {
-                        creating: true,
+                        mode: PickMode.Creating,
                         initial_section: section,
                         initial_position: position,
                         grab_offset: new Vector3(0, 0, 0),
@@ -247,83 +255,63 @@ export class QuestEntityControls implements Disposable {
         }
     };
 
-    private dragover = (e: Event) => {
+    private dragover = (e: EntityDragEvent) => {
         if (!quest_editor_store.current_area.val) return;
 
-        const detail = (e as CustomEvent<EntityDrag>).detail;
-        detail.data_transfer.dropEffect = "copy";
+        if (this.pick && this.pick.mode === PickMode.Creating) {
+            e.event.stopPropagation();
+            e.event.preventDefault();
 
-        if (this.selected && this.pick) {
-            const pointer_device_pos = this.renderer.pointer_pos_to_device_coords(
-                new Vector2(detail.offset_x, detail.offset_y),
-            );
+            if (e.event.dataTransfer) {
+                e.event.dataTransfer.dropEffect = "copy";
+            }
 
-            // TODO:
-            // if (e.buttons === 1) {
-            // User is transforming selected entity.
-            // User is dragging selected entity.
-            // if (e.shiftKey) {
-            // Vertical movement.
-            //     this.translate_vertically(this.selected, this.pick, pointer_device_pos);
-            // } else {
-            // Horizontal movement across terrain.
-            this.translate_horizontally(this.selected, this.pick, pointer_device_pos);
-            // }
-            // }
+            if (this.selected) {
+                const pointer_device_pos = this.renderer.pointer_pos_to_device_coords(e.event);
 
-            this.renderer.schedule_render();
+                if (e.event.shiftKey) {
+                    // Vertical movement.
+                    this.translate_vertically(this.selected, this.pick, pointer_device_pos);
+                } else {
+                    // Horizontal movement across terrain.
+                    this.translate_horizontally(this.selected, this.pick, pointer_device_pos);
+                }
+
+                this.renderer.schedule_render();
+            }
         }
     };
 
-    private dragleave = (e: Event) => {
+    private dragleave = (e: EntityDragEvent) => {
         if (!quest_editor_store.current_area.val) return;
 
-        const detail = (e as CustomEvent<EntityDrag>).detail;
-        if (detail.drag_element) detail.drag_element.style.display = "flex";
+        e.drag_element.style.display = "flex";
 
         const quest = quest_editor_store.current_quest.val;
 
-        if (quest && this.selected && this.selected.entity.type == detail.entity_type) {
+        if (quest && this.selected && this.pick && this.pick.mode === PickMode.Creating) {
             quest.remove_entity(this.selected.entity);
         }
     };
 
     private drop = () => {
         // TODO: push onto undo stack.
+        this.pick = undefined;
     };
 
-    private process_event(e: Event): void {
-        let offset_x: number;
-        let offset_y: number;
-
-        if (e instanceof MouseEvent) {
-            offset_x = e.offsetX;
-            offset_y = e.offsetY;
-        } else if (e instanceof CustomEvent) {
-            const detail = (e as CustomEvent<EntityDrag>).detail;
-
-            if (!("offset_x" in detail && "offset_y" in detail)) {
-                return;
-            }
-
-            offset_x = detail.offset_x;
-            offset_y = detail.offset_y;
-        } else {
-            return;
-        }
-
-        if (e.type === "mousedown" || e.type === "phantasmal-dragenter") {
+    private process_event(e: MouseEvent): void {
+        if (e.type === "mousedown") {
             this.moved_since_last_mouse_down = false;
         } else {
             if (
-                offset_x !== this.last_pointer_position.x ||
-                offset_y !== this.last_pointer_position.y
+                e.offsetX !== this.last_pointer_position.x ||
+                e.offsetY !== this.last_pointer_position.y
             ) {
                 this.moved_since_last_mouse_down = true;
             }
         }
 
-        this.last_pointer_position.set(offset_x, offset_y);
+        this.last_pointer_position.set(e.offsetX, e.offsetY);
     }
 
     /**
@@ -456,7 +444,12 @@ export class QuestEntityControls implements Disposable {
     }
 
     private stop_transforming = () => {
-        if (this.moved_since_last_mouse_down && this.selected && this.pick && !this.pick.creating) {
+        if (
+            this.moved_since_last_mouse_down &&
+            this.selected &&
+            this.pick &&
+            this.pick.mode === PickMode.Transforming
+        ) {
             const entity = this.selected.entity;
             quest_editor_store.push_translate_entity_action(
                 entity,
@@ -503,7 +496,7 @@ export class QuestEntityControls implements Disposable {
         }
 
         return {
-            creating: false,
+            mode: PickMode.Transforming,
             mesh: intersection.object as Mesh,
             entity,
             initial_section: entity.section.val,