TextArea.BackColor in 2018r3

With the changes in 2018r3 to accommodate Mojave Dark Mode my TextArea.BackColor code has broken. I can’t figure from all that I have read how to fix it.
The app presents answers to questions in textAreas of normal black text on normal white background. If user chooses correct answer I change the textArea backColor to green; if the user answers incorrectly I change the textArea backColor to red.
Running on High Sierra (so not even getting to Mojave dark mode yet) now the textArea with the backColor change is just blank (normal white with no text showing).

Any ideas?

Ignore this post. I just remembered that I had the window super as Sam Rowland’s mTKWindow. Changed back to standard Window and it work OK.

Never heard of that - got a link?

The mTKWindow class was a download attached to the July/August 2018 XDev Magazine article by Sam Rowlands about how to make your Xojo app work in Mojave dark mode. So far my testing of Xojo 2018r3 says that Sam’s hard work is no longer needed.