Ubuntu/Mint, Win10 guest becomes unresponsive on dual-screen host

[The Bright Side]

Hey guys! Anybody else experience this bug, where the Windows UI will almost freeze after switching to and from the VM?

Steps to Reproduce:
1. Launch Windows 10 VM on Linux Mint or Ubuntu host with a dual-screen setup
2. Keep it on either screen 1 or screen 2
3. Go back and forth between VM and programs running on Linux host a few times
4. Observe erratic behaviour and almost-freeze on VM

Current Results:
When running a single-screen Windows 10 VM on a dual-screen Ubuntu or Mint host, the VM sometimes becomes almost unresponsive. It will only very rarely react to mouse clicks or keystrokes, but when moving the mouse over the UI, hover effects (e.g. on buttons in the Office ribbon) still get triggered - erratically. Also, some keystrokes still work, e.g. pressing the Windows key does open the Start menu.

Expected Results:
The Windows 10 VM should always work.

Attachments:
I made a video that shows the issue: it's on youtu.be[slash]aYpDy9PcZJs
** Around halfway through the video, Microsoft Word reacts to CTRL+N keypresses I did before starting the recording
** During the video, I repeatedly click on various elements of the UI
Virtual Machine configuration: pasteboard.co[slash]HM5WJYN.png

Notes:
Repro Rate: rare
Issue experienced on and off for several years on Ubuntu or Mint hosts
Up until recently, this issue only occurred on one screen, so I kept the VM on the other screen and everything was fine. Since Nov 2018, it has started happening no matter what screen I open the VM on.
3D acceleration is disabled on this VM.

Any idea what I could do to fix this issue? Is there a setting I could activate or deactivate?

[The Bright Side]

Hello, Community and dev team! I found out that this issue is 100% reproducible after dragging MP3s from Nemo (Mint's file manager) into Audacity or VLC (playback apps). Perhaps it's something to do with the shared clipboard, where Windows gets confused if files are dragged from one app to another on the host?

[The Bright Side]

CORRECTION/UPDATE: I found out what's causing this issue!!

This issue always occurs when files are dragged from the host onto or over the client window without actually dropping them there.

Workaround is to disable drag'n'drop in Settings > General > Advanced.

[mpack]

Hmm. That sounds like a good candidate for a BugTracker ticket. I'm guessing that a drag and drop client is created when mouse movement is detected. I'm not sure why it would need to block though - that usually means lazy programming (not wanting to write it as a state machine, with a timeout).