Formatting is lost after some actions

[berndmoos]

• changing show/hide in Edit tiers menu resets formatting
• Undo after removing tiers resets formatting

[berndmoos]

See also #398

[berndmoos]

Did something about it, first tests were okay. @sarkipo : can you check the latest preview one of these days?

[sarkipo]

@berndmoos Yep, Undo remove tier and changing show/hide in Edit tiers did work properly and did not ruin the formatting!