MINOR: Editing a formula sets color-coding to "off"

[thrinn]

Since IMatch 2023.8.4 we can use color-coding also for formula-based categories. But each time the formula is edited the color-coding is reset to "off".
Steps to reproduce:

• Create a fomula-based category.
• Set color-coding to "active".
• Enter the formula editor.
• Leave the formula editor with "OK" (you don't have to actually change anything).
• Color-coding is set to "off".

Fortunately, it is just two clicks to activate the color-coding again: IMatch remembers the colors you set before. Therefore, it is just a small glitch.

[Mario]

This has been fixed for the next release.