Hello Matthias,
I think what you need to do is to create screen capture for each dialog of you application then
save the image in Stores.Regions. Just make sure to create a naming convention for your reference
images so that during execution, you'll know to which image the current dialog will be compared to.
Next is for you to create a function that will get the image capture of the current dialog of your application
and get the corresponding reference image from Stores.Regions based on the current dialog. Then will compare
the two images and report the result.
Finally, create a script that will start your application that you will be testing, loop until all dialogs of the application
is opened sequentially. Then for each opened dialog, call the function for comparing images created earlier.
I hope this helps.
Regards,
Ruel