If you use task 19 to check for a keypress and then open a file dialog and then release the key - as you would because the dialog is now open - and now select a file and hit open the key you detected is now 'stuck' until after you press and release it again.
If you hit cancel the key seems to 'stick' in the not pressed condition until after being pressed and released again.
The code I'm using to detect when a key detected in this way has just been pressed has always worked before.
Example code
here.
Lee.