Every now and then on the Mac OS X client, the Ctrl key behaves like it's been pressed while it's not. I haven't yet figured out what key combination triggers this, but I mostly experience this in Emacs which has lots of key combinations with Ctrl. Pressing Ctrl again makes it get back in sync.
For the record: I've seen this on my Mac mini with OS X 10.9, ThinLinc Client 4.1.1.
We got a customer report on issue 14942. The issue also describes a way to reproduce the problem:
"It can be caused by holding (cmd+shift+4) (used on mac to make a
I verified this on our 10.9 machine in the lab with ThinLinc in windowed mode, and it resulted in state 0x9 getting stuck. Pressing and releasing first shift, then cmd got me back to normal.
There are two bugs at play here. One is a server side issue where it gets confused about two Alt_L presses with a shift in between and without a release. This has been moved to bug 5258.
The other bug is that we do not see the release of Cmd and Shift when 4 is grabbed as a hot key. Need to add some logic for this, probably triggering a release of all keys like we do for loss of focus.