In other IDEs like Visual Studio Code you have a shortcut cmd-p which opens a popup window where you can search for the file you want to open. I think this could be a nice touch to the Fire IDE 
It’s the so called Go to File or Quick Open-feature foud in Visual Studio Code: https://code.visualstudio.com/docs/editor/editingevolved
Kind of like File|Open Quickly, or Command-Shift-O? 
Yeah!!! Only command-shift-o is not working for me, though
Hmm, does here… DO you have any global shortcuts configured that might override it? Does the menu show the shortcut?
Not that I am aware off and couldn’t find it in the Keyboard’s Shortcuts-tab in System Preferences. Actually, I totally forgot you can define global shortcuts! I don’t I am using it as a global shortcut as the Finder’s shortcut for Cmd-Shift-O is working as it opens Documents-folder.
For me it looks like this:
My version of Fire build 2399
Odd. Something external to Fire overrides it, then…
