An interesting point. I have BCC 2021 installed on the desktop and there is no BCC Boost Blend OBS (obsolete). Maybe its from Sapphire as the OP has recently updated by suggesting a Sapphire trial install, but I thought that Sapphire plugins are preceded by 's_' or similar, but then I don't have Sapphire so I can't be sure about that.
No problems here with changing the highlight button color on either my desktop or laptop (b434 in both cases).
Resolved. It is the problem of my system.
Would be interesting to know the solution ( can't change highlight button color ) since on my partner's system , those turned pink after upgrading to latest version . When correcting to the blue color , and saving and restarting , they are again pink :-)
@set : Thanks , will pass the message , I myself am not using magix softwares but follow up things since my partner in filming does and since I have been a long time sony's versions client knowing the software a little bit ( see my profile ) . In meanwhile troubleshooted my partner's HP Z840 and only thing I had to do is update the Visual C++ 2015-2019 and his pink panther mystery got resolved . ( would expect when such is a requirement for non-software engineers using this app , the program would install such by itself ( as adobe and avid do ) )