@Ronald-Koons ,
I never have found the need for using “First to Compare” button. When I start my comparison, I just put my “old” file on the left and “new” file on the right, and click the “compare” button, and it works exactly as I expect it to.
Okay, with a little experimenting: if I have all my files in the same view (so multiple tabs, none on the right), then if I click “First to Compare” in the “old” file, then “Compare” in the “new” file, it puts the one marked “first” on the left and the one where you clicked “Compare” on the right. And when i ended that compare, the “new” file moved back to the only active view with all the others. So the “First To Compare” button appears to be used only for marking the order of comparison when both files are starting from the same view.
FYI: If you still want a change in behavior (I don’t think you need one), the author of the Compare Plugin has an issues page where such requests should be made. However, the author of the Compare plugin is no longer working on that incarnation of the plugin, and is instead working on a “ComparePlus” plugin to replace it. There has been no timeframe given for the newly-named plugin. However, the author does have issues for the Compare Plugin that are marked for ComparePlus v1, so if you put in your request through the compare plugin issues page, they might be included in the replacement plugin.