bug#34819: 26.1; Blank help-echo tooltips for mode line menus

[Eli Zaretskii]

> Date: Tue, 12 Mar 2019 12:45:58 +1300
> From: Phil Sainty <psainty@orcon.net.nz>
> 
> Recipe from emacs -Q (and --with-x-toolkit=lucid)
> 
> * M-x text-mode
> * Mouse 1 click on "Text" in the mode line to open the menu
> * Hover over any of the menu items until the tooltip appears
> 
> For me, this produces tooltips of the appropriate dimensions, but the
> text itself is not visible.

I can only suggest to step with a debugger through x-show-tip and see
what's going on there.  It's hard to understand how come the frame is
shown, but the text produced by the same function is invisible.  Maybe
we are missing some X wizardry in that function.