Motivation / Problem

When a tool dragging operation is active:

• There is an ugly tooltip flickering effect when the mouse is moved outside of the OpenTTD window.
• The tooltip is not removed when the mouse is moved over a non-viewport internal window.

Description

• Do not create a tooltip when the mouse is not in the OpenTTD window, as it will be removed in the next mouse loop, creating ugly flickering.
• Remove viewport measurement tooltips when the mouse is not over a viewport.

Limitations

N/A

Checklist for review

Some things are not automated, and forgotten often. This list is a reminder for the reviewers.

• The bug fix is important enough to be backported? (label: 'backport requested')
• This PR affects the save game format? (label 'savegame upgrade')
• This PR affects the GS/AI API? (label 'needs review: Script API')
  • ai_changelog.hpp, gs_changelog.hpp need updating.
  • The compatibility wrappers (compat_*.nut) need updating.
• This PR affects the NewGRF API? (label 'needs review: NewGRF')
  • newgrf_debug_data.h may need updating.
  • PR must be added to API tracker