Bring back ability to show alt+tab (application swticher) on all monitors, when "Primary Monitor" is defined

After upgrading to Ubuntu 24.04 (and therefore xfce-4.16) recently, I've been struggling with a new change that happened in the issue linked below.

#350 - tabwin: New tweak to only show on the primary monitor

Because I have a "Primary Monitor" defined in display settings, the alt+tab application switcher is only ever showing up on the primary monitor. This makes it very hard to switch applications when not working on the primary monitor. While I have read and understand the use case described in the issue above, it seems to me to be a broad change made to streamline presentation mode, which is more of a niche scenario.

I think it feels more natural to have the switcher on all monitors by default. It's very disconcerting to be looking at a single monitor (that's not your primary), hit alt+tab, and see nothing. What's worse is when you're in a scenario where a monitor isn't functional (you're in the process of configuring a monitor), it can make it impossible to switch applications in some scenarios without just guessing how many times to hit alt+tab.

I also think tying the application of this setting to the "Primary Monitor" flag isn't the best design. I like having a primary monitor set, but it serves other purposes than just where the alt+tab UI will show. It helps keep my main xfce-panel always visible no matter which displays I have connected.

I understand that the previous issue had some back and forth about adding a new window manager tweak setting.

I have created and tested a patch locally that adds a new tweak "Display switcher on all monitors, even when primary monitor is set", which is off by default. With this new tweak, the application switcher shows on all monitors even if you have a primary monitor defined.

I'd like to submit a merge request for this (I'll go through the request fork access thing soon).

I understand that the most optimal way to support this may be some tweak to this setting's wording/functionality, but it can serve as a first effort. :-)