OK and Cancel Buttons missing in Expert Parameter Window

 
I have few Expert advisors and custom indicators installed in my MT4 terminal (build 646). After dragging en expert or a custom indicator into the window the parameters window opens only with RESET button (without "OK", "Cancel" buttons) - see attached screen shot. However For regular indicators - the parameters window does include those buttons. - why is it?  
 
rbd27:
I have few Expert advisors and custom indicators installed in my MT4 terminal (build 646). After dragging en expert or a custom indicator into the window the parameters window opens only with RESET button (without "OK", "Cancel" buttons) - see attached screen shot. However For regular indicators - the parameters window does include those buttons. - why is it?  
It has already been asked some times ago, please do some researches on the forum.
 
I could not find anything - can you give me a pointer to a place that describe how to solve this?