Atleast in my setup, In Display Fusion 7.1, the Maximize (ignoring splits) button does not seem to work for consistently.
Sometimes it just maximizes within one of the splits (last one), sometimes it maximizes within the split it is located in, and sometimes it actually works as expected and maximizes to the entire monitor. The keyboard shortcut always works.
I've been using the keyboard shortcut for weeks, and just started with the titlebar button yesterday.

My expectation is that this button should always maximize to the entire screen whether the current window is already maximized within the split or not maximized at all. I think Pressing the same button should restore back to what it was prior (whether it be maximized within split, or not maximized), but right now it seems to go back to maximized to a previous split monitor section, even though it wasn't maximized before.

It seems to happen with a lot of different types of windows, not sure if its all. Sometimes it works fine and sometimes it DF seems confused. I haven't quite worked at the trigger. Chrome is the one I see it the most on. the functionality of the button just isn't consistent with splits and I'm actually not sure how its supposed to act at this point. For example, right now I have a geany (text editor) window that is maximized inside the top left split. Clicking on the Maximize(ignoring splits) doesn't do anything sometimes. It remains maximized inside the split. Yet if I keep clicking it, it will at some point actually maximize properly. Double clicking seems to make it work 75% of time. I think some clicks may be ignored. Perhaps the overlay isn't being blocked by something? I do see the title bar flash sometimes, even when it doesn't maximize properly...

Another issue that occurs: When I doubleclick a maximized (inside split) window to restore its original size and then press the maximize (ignore splits) button, it will maximize the window into the the nearest virtual monitor rather than ignoring the split.

I've attached the troubleshoot log after a fresh boot. The symptoms don't occur until some usage, just not sure what triggers it. I do not often reboot the system and instead sleep anbd wake it up. Setup is 1 4K monitor split in two 2 1080p screens on the left and 2 slightly differently sized ones on the right.