That was seen as politically too close to Netscape's position. If you weren't there, you have no idea: Microsoft/Netscape was a trench war.
MS and Netscape both had a set of "foundation classes". Netscape's were much, much better, so, given the time constraints, I used those. Because of a little bit of window dressing in the scroll bars, somebody from a recent acquisition noticed it was Netscape's classes and, by itself, that killed my project and almost killed the entire deal.
The nineties were an ugly time for software development, thanks to Microsoft.