you can run sqldev in debug mode which will run more messages to the log panel
if it's hanging, then you could use the JSTACK utility in your JDK home to attach to the sql developer process and get a stack dump for debugging
Does this happen for ANY explain?
Thank You for reply.
there is short freeze with Explain Plan tab for query "select * from dual;"
With more tabs open and larger queries freeze is longer.
A see nothing on Logging Page.
With jstack I see org.GNOME.Accessibility.AtkWrapper.emitSignal, but I don't have any accessibility option enabled.
Or at least I don't know about any.
I attach one stack trace: jstack_9626.2017-08-22_08_56_36.zip.
I was using Oracle. I switched to Metal+ restart, but it works the same.
I tried old instalation 188.8.131.52.78 and it works great.
With 4.1 all interface works faster, but there is biggest difference on explain tab.
As others have not reported this issue, the only other possibility that comes to mind is corruption in the user settings. Could you try exiting SQL Developer, renaming the .\sqldeveloper\system184.108.40.206.1159, restart SQL Developer without settings migration, then try your explain plan test case again.