Hi,
This is a bit tricky. There is a solution available which shows you how to get a context menu:
You can apply this on the inputdlg function but you have to modify it. I do not recommend modifying MALAB function so best this here is to a make a copy, rename it to a unique name and start modifying it. Since the inputdlg function uses two functions which have private access (getnicedialoglocation.m and setdefaultbutton) you have to copy these files near to your modified example. Best way here, is to rename those functions two.
I prepared an example that shows you how to do it. I uploaded it here:
Note that the mentioned limitation (in the solution above) doesn't hold for this example.
