Deliver each drop to the zone under the cursor (#953)

app/MindWork AI Studio/wwwroot/app.js

@@ -286,4 +286,52 @@ window.localShortcut = {
         document.removeEventListener('keydown', handler, true)
         localShortcutHandlers.delete(id)
     }
+}
+
+// What floats above the page without ever being a drop target. Two of these take part in hit testing as
+// MudBlazor 8.15 stands: an open .mud-popover -- a closed one already declines pointer events through
+// .mud-popover:not(.mud-popover-open) -- and .mud-snackbar, which asks for them explicitly with
+// pointer-events: auto even though its container declines them, and snackbars appear constantly in this
+// app. Without this list, a drag would be answered by whatever happens to float on screen rather than by
+// the page below it. The remaining three are named because they surround those two: .mud-tooltip is the
+// content of a popover, while #mud-snackbar-container and .mud-badge-wrapper carry pointer-events: none
+// today and therefore never reach a hit test at all. Should a MudBlazor version drop that, they are
+// covered here already. Children of all of them have to be skipped as well, which is why the test below
+// uses closest rather than matches.
+const skippedDropOverlays = '.mud-popover, .mud-tooltip, .mud-snackbar, #mud-snackbar-container, .mud-badge-wrapper'
+
+// The drop zones of the app, addressed by the cursor position of a native drag and drop event.
+//
+// The arbitration between overlapping zones is left to the browser, and it can be: MudBlazor 8.15 gives
+// neither .mud-dialog-container nor .mud-overlay a pointer-events: none. Both fill the viewport while a
+// dialog is open, so a point beside the dialog box hits the container, and nothing there is a drop zone. A
+//  drop, therefore, cannot reach through an open dialog into the page behind it -- the very thing the app
+// used to enforce by counting layers in C#. That single CSS property carries this whole design, so it
+// belongs on the checklist for every MudBlazor major version, starting with the move to 9.
+window.dropZones = {
+
+    // Names the drop zone at the given viewport position, or null when there is none.
+    //
+    // The stack of elements is walked from the top down rather than asking for the topmost one alone,
+    // because the topmost one may be an overlay from the list above and skipping it has to reveal what
+    // lies beneath. The first element which is not skipped ends the walk, whether it belongs to a drop
+    // zone or not: anything unknown blocks on purpose, so a drop can never slip through something the
+    // user sees as being in the way. Within that element, closest resolves from the inside out, so a
+    // specific zone inside a page-wide one wins -- which is exactly the precedence we want.
+    hitTest: function (x, y) {
+        for (const element of document.elementsFromPoint(x, y)) {
+            if (element.closest(skippedDropOverlays))
+                continue
+
+            return element.closest('[data-drop-zone-id]')?.getAttribute('data-drop-zone-id') ?? null
+        }
+
+        return null
+    },
+
+    // Every drop zone currently in the DOM, in document order. This is for diagnostics only: when a drop
+    // lands nowhere, it answers the question of which zones would have been available at that moment.
+    list: function () {
+        return Array.from(document.querySelectorAll('[data-drop-zone-id]'), zone => zone.getAttribute('data-drop-zone-id'))
+    }
 }

app/MindWork AI Studio/wwwroot/changelog/v26.9.1.md

@@ -10,5 +10,9 @@
 - Added tool calling to the abilities you can state yourself in the expert provider settings. When you use a model AI Studio does not recognize as tool-capable, you can now declare that it is, the same way you already could for image input or reasoning.
 - Added local RAG as a beta feature, so the AI can answer from your own documents. You point AI Studio at a folder or at a single file, and it prepares those documents in the background so their contents can be found again later. Ask a question with such a data source selected, and AI Studio looks for the passages that fit your question and hands only those to the model, along with where each one came from. We will keep developing it together with the people who use it: to try it, open the app settings, allow preview features down to beta, and then enable the RAG feature. Many thanks to Paul Koudelka (`PaulKoudelka`) for around ten months of work on the concept and the implementation.
 - Added the setup for local data sources. You pick an embedding provider, and AI Studio asks for your confirmation before any document goes to a cloud service. It keeps up with your files as they change, shows the progress on a page of its own, and checks every document for hidden instructions before indexing it. Documents without readable text, such as scanned pages, are remembered as such, so AI Studio does not work through them again after every start — it comes back to them once they change.
+- Added support for several drop areas on the same page. More complex assistants can now receive files or folders by drag and drop at more than one place.
+- Added drag and drop to the input and output folder of the Batch Processing assistant: drop a folder onto either field to choose it.
+- Added ways to load text from a file and drop zones for them, throughout the assistants and dialogs. We went through them one by one, so many fields that used to accept typed text only now take the content of a file as well.
 - Improved loading web content in the assistants: it now uses the same reader as the Read Web Page tool, which extracts the main content of a page more reliably and skips navigation and boilerplate. Pages from your own network, including local servers, keep working as before. When a page cannot be read, AI Studio now says why instead of leaving the field empty.
 - Changed how provider trust and provider confidence work together. Marking a provider as trustworthy in a configuration no longer also satisfies a required confidence level: one says who runs the provider, the other how confidential it is. Organizations raise a provider's level in their own confidence scheme instead. This applies beyond local data sources, for example, when a model reads a page from your intranet.
+- Fixed a dropped file being processed several times, e.g., after the computer woke up from sleep.