Since a recent windows webex update, several other applications have stopped being able to use the ctrl-shift-m keystroke, even when obvious webex windows are not open. Using task manager to kill webex applications running in the background returns the keystroke to functionality. I've not discovered any other keystrokes that webex is filtering, but there certainly may be others.
I've done a clean uninstall using the CiscoWebexRemoveTool and reinstall with the current package (Version 41.10.0.20280, Revision number {79073E37-5756-438B-935C-A65F0F4A8000}) with no effect.
The page https://help.webex.com/en-US/article/7wr87q/Webex-%7C-Keyboard-Navigation-and-Shortcuts says that ctrl+shift+m is used to "turn music mode on/off" but that it is not "global".
1. This seems like this is a clear bug with ctrl-shift-m specifically as it appears to kick in only after a meeting but isn't disabled when the meeting has ended.
2. I would like to disable webex keyboard shortcuts generally (and this one specifically) but there isn't an obvious preference/setting option to do so.
3. webex should certainly not be filtering commonly used keystrokes, at least not by default, when it is not the focus as it prevents proper operation of other applications.