In Card Layout Image Aspect Ratio (maybe on other same kind of form field)
In france the separator is a comma: 1:1,5 in english it's a point 1:1.5 and the field manage the localized preference so it's not possible to use a point as the separator if the GUI language is set to french.
The preview of the layout is not updated is we use comma and i don't think the seeting is correctly save if i use comma in french GUI.
Another small pb occure. "Preview" in french is "Aperçu" so when exporting the App done with Preview Mode enabled, the Ç is outputed in UTF8 entities: %C3%A7
I think i'm gonna stay in English (us) for a while to avoid unexpected behaviour 😉