Brief summary of issue / Description of requested feature:

Room symbols are not shown consistently throughout different zoom levels

Steps to reproduce the issue / Reasons for adding feature:

1. Observe a zoom into the map. All colored rooms do have a symbol associated
2. One center room shows its symbol quickly after the first increase of zoom level
3. Focus the two top left rooms. They actually display then hide their symbol again!
4. The latest zoom level shows all room symbols. Notice how similar they are in size.

Error output / Expected result of feature

Room symbols should at best be shown at all zoom levels

Extra information, such as Mudlet version, operating system and ideas for how to solve / implement:

Current PTB, Win10
Zooming is done with scrolling the mouse wheel