bug#50993: 29.0.50; Problems when dragging the mouse over the toolbar

[Juri Linkov]

>> Tab dragging is implemented in tab-bar.el with this:
>>
>>    (define-key map [drag-mouse-1] 'tab-bar-mouse-move-tab)
>
> That's harmless because it doesn't use mouse-movement.

I confirm that your patch breaks nothing.

> IIUC dragging tabs from one frame to another is not supported (yet).

Yep, not yet.

> BTW the shape of the mouse pointer should change while dragging tabs.
> Currently there's absolutely no feedback wrt what's going on.

Please suggest how the shape of the mouse pointer could be changed
in [down-mouse-1], and restored in [drag-mouse-1].