Connecting different GUI sections

[faldzip]

if you have seg fault here:

instanceOfD->instanceofE->setText(...);

instanceOfD->instanceofE->setText(...);

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that means that one of those pointers: "instanceOfD" or "instanceofE" is invalid, maybe you forgot about creating object with new or forgot that you have deleted it with delete. Pasting your code here would be helpful in finding the problem. Another thing is that debugger is the right tool to investigate such problems, so you can give it a try :]