Drag and drop to save file on the standard save file dialog
In of the GUI of RISC OS when saving a file you can drag and drop the file before it has been created to the desired output directory using the mouse.
Look at this video of this feature: https://youtu.be/oL4w3AK6Qpw?t=750
Some screenshots from the video:
The save dialog:
Dragging the file to the output directory:
Dropping it has placed it and saved in the desired directory.

Great pointer to RISC OS who set the standard when it comes to drag-and-drop in many ways.
We want it to work the other way around though, because this is our rough guideline: Drag a file from Filer into the Save dialog to save the file under the name of the existing file, thus overwriting it.
But this is currently broken because the drag-and-drop operation results in a file:/// URI rather than a path.
I just take the first seven characters off.
No, there must be a proper way to do this. Something like FmPathList* srcPaths = pathListFromQUrls(data->urls());.