program under DDD receive SIGINT while mouse moves.

I use DDD through VNC. I suppose my problem only occurs under these
circumstances because I don’t remember having seen that before.
I use DDD 3.3.2.
When I run a program in DDD, and I move the mouse over the DDD window, I
often receive the following message:

Program Received SIGINT, Interrupt.
[switch to process xxxxxx]
0xb0326bfe in MsgReceive () from /x86/lib/

Does anybody know something about this problem?