Hello, welcome to the Community. We understand the disappointment in the Messages icon not changing to match the theme.
The Messages app is Google Messages, unless you have downloaded another app. Typically, Samsung themes will only apply to Samsung apps. If you prefer, you can download the Samsung Message app from the Galaxy Store. However, not all features are supported by service providers.
You can try using Theme Park in the Good Lock app to customize your icons. Good Lock can be found in the Galaxy Store.
We hope this helps. Other Members may also have suggestions that might help.
Be sure to click " ✓ Accept as Solution" when you find an answer that works for you.
Please note, notification emails are a DO NOT REPLY address, you must log-in on the community page in order to respond.
