Created attachment 181229 [details] Concept art. Currently, when clicking on something that opens the File Picker, will cause the File Picker to materialize on the center of the screen. However, it would be more aesthetically pleasing if it made the File Picker fade and grow from the cursor last click location, somewhat reusing the Panel's animation for launching/minimizing windows.
That's kind of a cool idea. A KWin effect would be necessary for this. However, the devil's in the details. What if a file picker is invoked from the keyboard, not the mouse? What if an app opens a dialog independent of user action? Then the dialog appearing out of the pointer would feel very weird. And I'm not sure a KWin effect could distinguish the difference. This is probably something you should prototype yourself to see if you can work out all the issues. Once it's good enough, submit it to KWin!
Maybe having the effect appear from the last clicked/tapped position would be easier to implement? It would look better when windows don't appear immediately.
That could solve the problem of the effect not making any sense whenever the keyboard is used instead of the mouse.