Hi Curt, it's hard to do it in one step unless your windows are small enough to see everything at the same time. Could you test doing it in two steps?

(1) Click on the tab you want to move and drag it down over the page, then release the mouse.

The tab should detach to a separate window. Does that part work?

Reduce the size of that window so you can see other windows in the background.

(2) Drag the tab in the detached window to the tab bar where you want it to go and drop.

Firefox should display a little insertion icon showing where it will put the tab so you can place it among the existing tabs. Does that part work?

I have tried doing the step #1 as described and nothing happens. When I click, hold, and start to drag nothing changes. No any indication at all that the window is going to move to where ever I am dragging to.

If it helps any I am on and iMac using Mac OS Sequoia 15.1.1.

Could you check whether this setting has been changed:

(1) In a new tab, type or paste about:config in the address bar and press Enter/Return. Click the button accepting the risk.

More info on about:config: Configuration Editor for Firefox. The moderators would like us to remind you that changes made through this back door aren't fully supported and aren't guaranteed to continue working in the future.

(2) In the search box in the page, type or paste browser.tabs.allowTabDetach and pause while the list is filtered

(3) If the preference is bolded and has a value of false, double-click it (or click the Toggle button or Reset button at the right end of the row) to restore the default value of true

It says true already.

Okay, I can't explain that. Hopefully a Mac user can chime in.

Thanks for trying. I appreciate the effort!

Are you dragging the tab to the Tab bar in the other window?

There is also "Move Tab -> Move to New Window" in the context menu of a tab. Does that work for you?