Has anyone figured out a keyboard shortcut to globally strikethrough selected text in any OS X app?
Hey I just came across this question because today I just started to use Stickies as a To-Do list for things I need to finish over the day and I also wanted to have that feature that you strikethrough items or text you are done with…

I think an easy workaround for this is that you have lets say 3 items, then you go to mark your first item with the strikethrough from the Fonts panel and then select that all the item and go to Font > Copy Style (Opt+Cmd+C) and then because it is copied in the Stickies app, after, anytime you use the shortcut Opt+Cmd+V (Paste Style) over a selected item it will paste the strikethrough style anytime later on the app, even if you have any other copied item in your clipboard.