MsgWaitForMultipleObjects/Ex does not return on WM_TIMER

If QS_TIMER is specified in dwWakeMask parameter of MsgWaitForMultipleObjects/Ex function, it will not exit even if a timer was expired in message queue and WM_TIMER message should be generated.
If mouse is moved or key is pressed MsgWaitForMultipleObjects returns and pending WM_TIMER messages are generated and can be processed.

Due to this bug PuTTY does not update terminal screen until you move mouse or press a key on keyboard.

It is possible that PuTTY mouse move bug is the same as FireFox mouse move bug...