Just what I wanted.

Tweaks: I set it up so that I have the TMP icon on toolbar that opens a TMP *view* in a new tab (which as a view you can delete after using without deleting its contents) and set to small ("eliminate spaces around"). Then you can see all the windows panoptically and can move documents easily between them.

DO NOT PRESS THE "X" IN THE RED CIRCLE unless you want to delete the whole individual window. Instead, to delete tabs within a window, right-click the tab icons, select as many as you want, then go to the trash can at the TMP tab to click and delete.

The "save" feature works. Though will it if I close Firefox? Time will tell.

If I leave the main TPM view (e.g. to change the name of a window), pressing window refresh gets me back to the main view.