Description:
I start a session in Base, I create a simple table, I close Base hitting x in the upper right corner: IT HANGS.
If I save with file->save or the floppy button and close, It NOT hangs.

Actual Results:  
I start a session in Base.
I create and save a database HSQLDB.
I create a simple table. 
I close Base hitting x in the upper right corner.
It ask me to save; I hit yes and base HANGS.
 
If I do the same trings but before closing Base I go to File->Save or use the Floppy button, It closes correctly.
 

Expected Results:
Close and save properly.


Reproducible: Always


User Profile Reset: No



Additional Info:


User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:57.0) Gecko/20100101 Firefox/57.0