Is there a Keyboard Shortcut to put the focus on Firefox's Sidebar?

Is there a Keyboard Shortcut to put the focus on Firefox's Sidebar?

I use the Add-On "Bookmark search plus 2" which is really awesome. When I activate it's Keyboard Shortcut (Ctrl + Q), the Sidebar opens, but I have to use my mouse to click on the Sidebar to grant it focus. I looked around online and haven't found anything. If anyone knows of a way, a Keyboard Shortcut, a tool or another Add-On perhaps, please let me know! Cheers!

#firefox