Admin Area BuildMode Can Break

[Kyep]

Issue Description: Exiting area buildmode without changing to another buildmode first creates a permanent yellow overlay on tiles.

What did you expect to happen: Upon existing buildmode (area submode) the markup that this mode applies to tiles should be removed.

What happened instead: The yellow marker persisted.

Why is this bad/What are the consequences: Creates a permanent yellow overlay on tiles.

Steps to reproduce the problem:

1. As admin, enable event->Buildmode
2. Switch to 'area edit' buildmode
3. Right click a turf with an area
4. yellow overlay appears
5. left click a few times to spread the yellow overlay (representing the area) to new turfs
6. click the 'X' at top left to exit buildmode
7. observe that the yellow overlay does not go away

Extra information: Changing to another buildmode before exiting buildmode entirely DOES remove the yellow overlay. But directly exiting buildmode from 'area edit' buildmode DOES NOT remove the yellow overlay.

[Spacemanspark]

Relogging does fix the issue at least

[Sirryan2002]

Confirmed still an issue