Using latest versions of Msg + Plus! + have skin installed, clean installs of all three, installed in this order: MSN messenger, Skin, Plus.

If a new conversation tab is opened, the colour of the tab bar becomes that of the original MSN theme, until window recieves focus.

The theme of the tab bar then changes to be the same as the rest of MSN Messenger, and stays that way until another tab is created, at which point the theme changes back to that in original MSN7, until the conversation window gets focus again.

Could someone force the theme to applied to the tab bar whenever a new tab is created, as if it just got focus?

The RGB colours in the skin could be effecting this, what skin are you using?

Have you used msgplus tweak at all to change the tabs colours or rolando's slate tab colour fixer?