I could point out many previous posts on this topic. Each time I install a new JDev release, the backspace key and spacebar stop working. There is a fix that involves re-assigning the accelerators, though this cannot be done for the Backspace key b/c its not possible to 'type' a backspace into the accelerator field. So, then you need to go in and find the accelerator config file and edit in there.
SQL Developer apparently shares the same UI and thus the same issue.
Posts on this issue related to JDev:
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Posts related to SQLDeveloper with the same issue:
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1690123
1252848
Supposedly the problem goes away if I install the Oracle provided JVM, but can't this bug just be fixed? I really don't want a Oracle JVM and the OS X version of JDev doesn't have a JVM available, so its not a solution.
Off to figure out what config file to edit. Bah. I think I'm just done for the day. Please fix this.