cursor can't move

[gc]

When I type my code, the cursor always moves to the end of line without space to the most right character. Whatever I use space bar or tab key the cursor back to left.
What cause this happen? How to solve this problem and how to avoid it?
Please help and thanks a lot in advance!
George

 

[hennep]

this happens when there is an open form with a timer.
try to close all forms when you are working in a code window( also hidden forms ).