diff --git a/core/src/jsMain/kotlin/world/phantasmal/core/JsExtensions.kt b/core/src/jsMain/kotlin/world/phantasmal/core/JsExtensions.kt
index b9fd8d09..a27af3fa 100644
--- a/core/src/jsMain/kotlin/world/phantasmal/core/JsExtensions.kt
+++ b/core/src/jsMain/kotlin/world/phantasmal/core/JsExtensions.kt
@@ -1,11 +1,12 @@
 package world.phantasmal.core
 
+import kotlinx.coroutines.await
 import world.phantasmal.core.externals.browser.WritableStream
 
-inline fun <S : WritableStream, R> S.use(block: (S) -> R): R {
+suspend inline fun <S : WritableStream, R> S.use(block: (S) -> R): R {
     try {
         return block(this)
     } finally {
-        close()
+        close().await()
     }
 }
diff --git a/web/src/main/kotlin/world/phantasmal/web/core/files/FilesExtensions.kt b/web/src/main/kotlin/world/phantasmal/web/core/files/FilesExtensions.kt
index c4861cad..63ba17aa 100644
--- a/web/src/main/kotlin/world/phantasmal/web/core/files/FilesExtensions.kt
+++ b/web/src/main/kotlin/world/phantasmal/web/core/files/FilesExtensions.kt
@@ -1,9 +1,16 @@
 package world.phantasmal.web.core.files
 
+import kotlinx.coroutines.await
+import world.phantasmal.core.use
 import world.phantasmal.lib.Endianness
+import world.phantasmal.lib.buffer.Buffer
 import world.phantasmal.lib.cursor.Cursor
 import world.phantasmal.lib.cursor.cursor
 import world.phantasmal.webui.files.FileHandle
 
 suspend fun FileHandle.cursor(endianness: Endianness): Cursor =
     arrayBuffer().cursor(endianness)
+
+suspend fun FileHandle.Fsaa.writeBuffer(buffer: Buffer) {
+    writableStream().use { it.write(buffer.arrayBuffer).await() }
+}
diff --git a/web/src/main/kotlin/world/phantasmal/web/questEditor/controllers/QuestEditorToolbarController.kt b/web/src/main/kotlin/world/phantasmal/web/questEditor/controllers/QuestEditorToolbarController.kt
index cac5cccf..e32c8cbb 100644
--- a/web/src/main/kotlin/world/phantasmal/web/questEditor/controllers/QuestEditorToolbarController.kt
+++ b/web/src/main/kotlin/world/phantasmal/web/questEditor/controllers/QuestEditorToolbarController.kt
@@ -1,7 +1,6 @@
 package world.phantasmal.web.questEditor.controllers
 
 import kotlinx.browser.document
-import kotlinx.coroutines.await
 import mu.KotlinLogging
 import org.w3c.dom.HTMLAnchorElement
 import org.w3c.dom.url.URL
@@ -15,6 +14,7 @@ import world.phantasmal.observable.value.list.MutableListVal
 import world.phantasmal.observable.value.list.mutableListVal
 import world.phantasmal.web.core.PwToolType
 import world.phantasmal.web.core.files.cursor
+import world.phantasmal.web.core.files.writeBuffer
 import world.phantasmal.web.core.stores.UiStore
 import world.phantasmal.web.questEditor.models.AreaModel
 import world.phantasmal.web.questEditor.stores.AreaStore
@@ -37,10 +37,14 @@ class QuestEditorToolbarController(
     private val areaStore: AreaStore,
     private val questEditorStore: QuestEditorStore,
 ) : Controller() {
-    private val questLoaded = questEditorStore.currentQuest.isNotNull()
     private val _resultDialogVisible = mutableVal(false)
     private val _result = mutableVal<PwResult<*>?>(null)
     private val _saveAsDialogVisible = mutableVal(false)
+    private val saving = mutableVal(false)
+
+    // We mainly disable saving while a save is underway for visual feedback that a save is
+    // happening/has happened.
+    private val savingEnabled = questEditorStore.currentQuest.isNotNull() and !saving
     private val files: MutableListVal<FileHandle> = mutableListVal()
     private val _filename = mutableVal("")
     private val _version = mutableVal(Version.BB)
@@ -59,12 +63,13 @@ class QuestEditorToolbarController(
 
     // Save as
 
-    val saveEnabled: Val<Boolean> = questLoaded and files.notEmpty and BrowserFeatures.fileSystemApi
+    val saveEnabled: Val<Boolean> =
+        savingEnabled and files.notEmpty and BrowserFeatures.fileSystemApi
     val saveTooltip: Val<String> = value(
         if (BrowserFeatures.fileSystemApi) "Save changes (Ctrl-S)"
         else "This browser doesn't support saving to an existing file"
     )
-    val saveAsEnabled: Val<Boolean> = questLoaded
+    val saveAsEnabled: Val<Boolean> = savingEnabled
     val saveAsDialogVisible: Val<Boolean> = _saveAsDialogVisible
     val filename: Val<String> = _filename
     val version: Val<Version> = _version
@@ -170,7 +175,7 @@ class QuestEditorToolbarController(
                 if (binFile == null || datFile == null) {
                     setResult(Failure(listOf(Problem(
                         Severity.Error,
-                        "Please select a .qst file or one .bin and one .dat file."
+                        "Please select a .qst file or one .bin and one .dat file.",
                     ))))
                     return
                 }
@@ -198,44 +203,46 @@ class QuestEditorToolbarController(
     }
 
     suspend fun save() {
-        if (saveEnabled.value) {
-            try {
-                val quest = questEditorStore.currentQuest.value ?: return
-                val headerFilename = filename.value.trim()
+        if (!saveEnabled.value) return
 
-                files.value.find { it.extension().equals("qst", ignoreCase = true) }
-                    ?.let { qstFile ->
-                        val buffer = writeQuestToQst(
-                            convertQuestFromModel(quest),
-                            headerFilename,
-                            version.value,
-                            online = true,
-                        )
+        try {
+            saving.value = true
 
-                        qstFile.writableStream()!!.use {
-                            it.write(buffer.arrayBuffer).await()
-                        }
-                    }
+            val quest = questEditorStore.currentQuest.value ?: return
+            val headerFilename = filename.value.trim()
+            val files = files.value.filterIsInstance<FileHandle.Fsaa>()
 
-                val binFile = files.value.find { it.extension().equals("bin", ignoreCase = true) }
-                val datFile = files.value.find { it.extension().equals("dat", ignoreCase = true) }
-
-                if (binFile != null && datFile != null) {
-                    val (bin, dat) = writeQuestToBinDat(
-                        convertQuestFromModel(quest),
-                        version.value,
-                    )
-
-                    binFile.writableStream()!!.use { it.write(bin.arrayBuffer).await() }
-                    datFile.writableStream()!!.use { it.write(dat.arrayBuffer).await() }
-                }
-            } catch (e: Throwable) {
-                setResult(
-                    PwResult.build<Nothing>(logger)
-                        .addProblem(Severity.Error, "Couldn't save file.", cause = e)
-                        .failure()
+            files.find { it.extension().equals("qst", ignoreCase = true) }?.let { qstFile ->
+                val buffer = writeQuestToQst(
+                    convertQuestFromModel(quest),
+                    headerFilename,
+                    version.value,
+                    online = true,
                 )
+
+                qstFile.writeBuffer(buffer)
             }
+
+            val binFile = files.find { it.extension().equals("bin", ignoreCase = true) }
+            val datFile = files.find { it.extension().equals("dat", ignoreCase = true) }
+
+            if (binFile != null && datFile != null) {
+                val (bin, dat) = writeQuestToBinDat(
+                    convertQuestFromModel(quest),
+                    version.value,
+                )
+
+                binFile.writeBuffer(bin)
+                datFile.writeBuffer(dat)
+            }
+        } catch (e: Throwable) {
+            setResult(
+                PwResult.build<Nothing>(logger)
+                    .addProblem(Severity.Error, "Couldn't save file.", cause = e)
+                    .failure()
+            )
+        } finally {
+            saving.value = false
         }
     }
 
@@ -254,32 +261,42 @@ class QuestEditorToolbarController(
     }
 
     fun saveAsDialogSave() {
+        if (!saveAsEnabled.value) return
+
         val quest = questEditorStore.currentQuest.value ?: return
-        val headerFilename = filename.value.trim()
-        val filename =
-            if (headerFilename.endsWith(".qst")) headerFilename
-            else "$headerFilename.qst"
-
-        val buffer = writeQuestToQst(
-            convertQuestFromModel(quest),
-            headerFilename,
-            version.value,
-            online = true,
-        )
-
-        val a = document.createElement("a") as HTMLAnchorElement
-        val url = URL.createObjectURL(
-            Blob(
-                arrayOf(buffer.arrayBuffer),
-                obj { type = "application/octet-stream" },
-            )
-        )
 
         try {
-            a.href = url
-            a.download = filename
-            document.body?.appendChild(a)
-            a.click()
+            saving.value = true
+
+            val headerFilename = filename.value.trim()
+            val filename =
+                if (headerFilename.endsWith(".qst")) headerFilename
+                else "$headerFilename.qst"
+
+            val buffer = writeQuestToQst(
+                convertQuestFromModel(quest),
+                headerFilename,
+                version.value,
+                online = true,
+            )
+
+            val a = document.createElement("a") as HTMLAnchorElement
+            val url = URL.createObjectURL(
+                Blob(
+                    arrayOf(buffer.arrayBuffer),
+                    obj { type = "application/octet-stream" },
+                )
+            )
+
+            try {
+                a.href = url
+                a.download = filename
+                document.body?.appendChild(a)
+                a.click()
+            } finally {
+                URL.revokeObjectURL(url)
+                document.body?.removeChild(a)
+            }
         } catch (e: Throwable) {
             setResult(
                 PwResult.build<Nothing>(logger)
@@ -287,11 +304,9 @@ class QuestEditorToolbarController(
                     .failure()
             )
         } finally {
-            URL.revokeObjectURL(url)
-            document.body?.removeChild(a)
+            dismissSaveAsDialog()
+            saving.value = false
         }
-
-        dismissSaveAsDialog()
     }
 
     fun dismissSaveAsDialog() {
diff --git a/webui/src/main/kotlin/world/phantasmal/webui/files/Files.kt b/webui/src/main/kotlin/world/phantasmal/webui/files/Files.kt
index a22f7b78..fc7c8064 100644
--- a/webui/src/main/kotlin/world/phantasmal/webui/files/Files.kt
+++ b/webui/src/main/kotlin/world/phantasmal/webui/files/Files.kt
@@ -18,21 +18,9 @@ import world.phantasmal.webui.BrowserFeatures
 import world.phantasmal.webui.dom.disposableListener
 import world.phantasmal.webui.obj
 import kotlin.coroutines.resume
-import kotlin.js.Promise
 
-@OptIn(ExperimentalCoroutinesApi::class)
-class FileHandle private constructor(
-    private val handle: FileSystemFileHandle?,
-    private val file: File?,
-) {
-    constructor(file: File) : this(null, file)
-    constructor(handle: FileSystemFileHandle) : this(handle, null)
-
-    val name: String = handle?.name ?: file!!.name
-
-    init {
-        require((handle == null) xor (file == null))
-    }
+sealed class FileHandle {
+    abstract val name: String
 
     /**
      * Returns the filename without extension if there is one.
@@ -44,20 +32,29 @@ class FileHandle private constructor(
      */
     fun extension(): String? = filenameExtension(name)
 
-    /**
-     * Returns a writable stream if this [FileHandle] represents a [FileSystemFileHandle].
-     */
-    suspend fun writableStream(): FileSystemWritableFileStream? =
-        handle?.createWritable()?.await()
+    suspend fun arrayBuffer(): ArrayBuffer =
+        getFile().arrayBuffer().await()
 
-    suspend fun arrayBuffer(): ArrayBuffer = suspendCancellableCoroutine { cont ->
-        getFile()
-            .then { it.arrayBuffer() }
-            .then({ cont.resume(it) {} }, cont::cancel)
+    protected abstract suspend fun getFile(): File
+
+    /**
+     * File system access API file handle.
+     */
+    class Fsaa(private val handle: FileSystemFileHandle) : FileHandle() {
+        override val name: String = handle.name
+
+        suspend fun writableStream(): FileSystemWritableFileStream =
+            handle.createWritable().await()
+
+        override suspend fun getFile(): File =
+            handle.getFile().await()
     }
 
-    private fun getFile(): Promise<File> =
-        handle?.getFile() ?: Promise.resolve(file!!)
+    class Simple(private val file: File) : FileHandle() {
+        override val name: String = file.name
+
+        override suspend fun getFile(): File = file
+    }
 }
 
 class FileType(
@@ -86,7 +83,7 @@ suspend fun showFilePicker(types: List<FileType>, multiple: Boolean = false): Li
                 }.toTypedArray()
             }).await()
 
-            fileHandles.map(::FileHandle)
+            fileHandles.map(FileHandle::Fsaa)
         } catch (e: Throwable) {
             // Ensure we return null when the user cancels.
             if (e.asDynamic().name == "AbortError") {
@@ -103,7 +100,7 @@ suspend fun showFilePicker(types: List<FileType>, multiple: Boolean = false): Li
             el.multiple = multiple
 
             el.onchange = {
-                cont.resume(el.files!!.asList().map(::FileHandle))
+                cont.resume(el.files!!.asList().map(FileHandle::Simple))
             }
 
             // Ensure we return null when the user cancels.