Debugging a XWindows code (gdb) terminal looses keyboard focus

I am debugging a large XWindows program.
In the past (some mounthes ago)with gdb I could set a breakpoint on a callback and debug it.
[this was not true for popup callbacks in this case all the system was blocked and a reboot was necessary]
Presently the breakpoint is honoured but the keyboard focus is lost for the terminal and I cannot type anything.
The terminal must be closed at higher level.
Any suggestion?
Thank You in advance
Mario De Poli