I'm using RubyMine and I can't find how to configure the shortcuts so that when the Git panel is open, clicking on some file with changes will open its diff view (not the "Preview Diff" but as a new tab)
I tried to change the "Show diff" options to work on double click, but is didn't opened the file as diff, but just the file in a new tab
What do you mean by preview diff? A diff should be opened by default as tab. However, if you want to open the next diff as a new tab this needs to be configured: enter image description here