This problem is already reported as bug in issue SNAP-671. I observed it on my computer (windows 7) too.
I did the following.
loading a Sentinel-2 product
resampling to 20 m spatial resolution a window opens giving the message: "The target product has successfully been created … . Actual processing of source to target data will be performed only on demand … .
Within the box opened there is a button to click for “Don’t show this message anymore”
I clicked on this button and after some more actions using the mouse I recognized that there is no more keyboard input possible.
I found the way back:
I opened menu tools | options. The options window opens and directly on the first page is a point “other settings” with a button to click for “Show suppressed message dialogs again”. After activating this option by clicking on the button I had my keyboard back.
I hope this helps the developers to locate the error and helps other users to get their keyboard reactivated.
So it is not only a windows problem. We have now 3 reports. Windows 7, Windows 10 and Ubuntu.
And what the hell have the suppressed dialogs to do with the keyboard?
Have you replaced the jre folder in the installation directory or did you change the jdkhome property in etc/snap.conf?
Just installing a different Java version does not affect SNAP, because it comes with its own JRE.
Turn off the filter keys from the setting options and then check for the errors. If you don’t know how to do this then check this article by ValidEdge it might be useful to follow the steps correctly.