Opening file in right pane

Hi,

A lot of the time I want to work on two files side by side in split pane view. This works fine, but if I have a file open in the left pane, and want to open another file in the right panel I can't seem to do it. The second file opens by default in the left pane, I have to click 'Move to opposite group' but then the left pane jumps to some random file and I have to find the original one again. Is there an easier way to do this?

Thanks