I wanted to comment out the line in DBeaver, so I used Ctrl+- keys. But it didn't work. So I tried Ctrl+Shift+- and it worked in a wrong way: this shortcut opened the same query space, and when I pressed the same shortcut again - it has gone.
I googled it, but still don't know what is the name of this function. What is it?
The shortcut that you should be using to comment is Ctrl+/ for a single line and Ctrl+Shift+/ for multi line comment as per DBeaver documentation.
Coming to your question, they have not mentioned about Ctrl+Shift+- it in their docs but it does open another another SQL editor window for you which indicates the purpose is just it.