[Bug]: Wrong map grids are sometimes shown

[Baaaaaz]

Describe the Bug

If you run the currently nightly build (e.g. MapTool-nightly-20250815.exe) or gradle run Develop and go to create a new map or edit an existing map, all maps in the campaign thereafter seem to show the grid type of that new map/edited map/map that was selected at the time of opening the New Map dialog.

To Reproduce

View -> Show Grid

Map -> New Map...
Set name to square
Select square cell type
Click OK

Map -> New Map...
Set name to iso
Select iso cell type
Click OK

Select map "square"
Observe the square map is showing the iso grid

Map -> New Map...
Click Cancel
Observe the map is refreshed and now correctly shows the square grid
Select map "iso"
Observe the iso map is showing the square grid

Map -> Edit Map...
Observe the iso map still shows the square grid
Rename to hex and change the cell type to a hex
Switch to the "square" map
Observe it shows the hex grid

Save as a new campaign file
Reopen the campaign file
See grids are displayed correctly for each map

Map -> New Map...
Set name to iso
Select iso cell type
Click OK
Observe all other maps (i.e. "square" and "hex") now show the iso grid

Expected Behaviour

When showing a map's grid, it should be the one for that map not another map.

Screenshots

No response

MapTool Info

MapTool-nightly-20250815, Develop

Desktop

No response

Additional Context

NOT observed in 1.18.3