I just tried to dubble tap on the widget and expected to see the compare mode.
Would it not be a cool and intuitive shortcut to have a double tap on the widget perform the same action as a double tap on the same graph in the main app, meaning to open the compare mode for that graph?
Best regards!
TLDR: No. Too hard. Prone to bugs/problem.
Widgets are special. Flowx doesn’t have direct control of the widgets. Essentially, Flowx tells Android to show something in the widget and the Android OS runs their code to show the stuff. Also Flowx tells Android what to do if a user clicks on a widget. Widgets don’t have a double clock option. So the way around this is to detect a double click by checking if Android tries to open Flowx twice within a few hundred milliseconds.
Double tap on widgets is hard to do and prone to bugs/issues - as we know - so it probably not worth it.
Programming widgets suck. They break on different phones. Developers hate developing widgets.
Ha, ha, just searched about Android Widget development and found this:
Are Android widgets dying?
Read the first post - it sounds like they are talking about the Flowx widget 
Bummer!
It would have been nice.
But I totally understand your reasoning and priorities: