bug#73050: 30.0.90; Empty tool tip when hovering over tab-bar separator

[Juri Linkov <juri@linkov.net>]

>> >> This is only a minor issue. After enabling `tab-bar-mode' when hovering
>> >> with the mouse over the `tab-bar-separator' space, an empty tool tip
>> >> will be shown after a short delay.
>> >>
>> >> To reproduce:
>> >>
>> >> 1. Start emacs -Q
>> >> 2. M-x tab-bar-mode
>> >> 3. Move the mouse pointer over the space right after the "*scratch*" tab
>> >>
>> >> Would it make sense to somehow prevent displaying blank tool tips, e.g.,
>> >> via the following advice? Or maybe blank tool tips could be prevented on
>> >> the tab-bar level?
>> >>
>> >> (defun x-show-tip-adv (str &rest _) (string-blank-p str))
>> >> (advice-add #'x-show-tip :before-until #'x-show-tip-adv)
>> >
>> > Juri, can we prevent such empty tooltips from being shown by tab bar?
>>
>> Maybe this unasked-for default fallback is not needed after all:
>>
>> diff --git a/src/xdisp.c b/src/xdisp.c
>> index f9a10267bad..18834c6b781 100644
>> --- a/src/xdisp.c
>> +++ b/src/xdisp.c
>> @@ -15155,8 +15155,6 @@ note_tab_bar_highlight (struct frame *f, int x, int y)
>>    help_echo_object = help_echo_window = Qnil;
>>    help_echo_pos = -1;
>>    help_echo_string = AREF (f->tab_bar_items, prop_idx + TAB_BAR_ITEM_HELP);
>> -  if (NILP (help_echo_string))
>> -    help_echo_string = AREF (f->tab_bar_items, prop_idx + TAB_BAR_ITEM_CAPTION);
>>  }
>>
>>  #endif /* HAVE_WINDOW_SYSTEM */
>
> Do you remember why was this introduced?

It was copy-pasted from tool-bar code.