How can mouse clicks stop working in Windows but I can move the mouse?

Situation:

• Windows 2008 Server with SP2 64 Bit used as "Terminal Server", Direct X 11
• Office 2007 32 Bit
• .net add-in for PowerPoint using WPF, nlog, Lucene
• the add-in is for end-users and does not require RDP (this particular client uses terminal server)

Complication:

• After starting PowerPoint (with the add-in loading) mouse clicks are not working any more
• the mouse cursor keeps moving, the machine is generally responsive
• the behavior persists even after killing the PowerPoint process
• the behavior persists even after re-connecting to the terminal session
• the only way to restore the mouse clicks is by terminating the session

Solutions

• How to diagnose why Windows stops receiving Mouse clicks?
• What are possible causes for this (drivers, display, RDP etc.)

Unfortunately the behavior does not reproduce on a test system.

Solution 1:

This is probably due to WPF bug https://social.msdn.microsoft.com/Forums/vstudio/en-US/ac81b552-44ac-4410-a5cd-4dbf6132a634/wpf-apps-stop-responding-to-touches-while-mouse-continues-to-work?forum=wpf

Recommendations are the following:

• upgrade OS
• upgrade Office (2007 is way too old, also 32 bit may be incompatible with 64 bit OS).
• check that the client uses latest RDP client as well (Windows 7/8 has a different RDP client than, say, Windows XP)
• test the behaviour with same client on the test platform.

Also, quick fix for you (if this is a business-cirtical situation) - if the problem exists only for one client, and you need to fix it ASAP, install VNC server on the Win server and let the client use VNC (RealVNC, for example).