I don't see the skin bug where the Titlebar Color continually counts up until a skin is loaded (currently only VST3 32 and 64, previously only VST2) listed. It doesn't have anything to do with pasting a value as previously reported.
Here's a short video showing this in the latest Reaper win10x64.
https://imgur.com/a/U32dPet
I add a track and plugin (at the same time by choosing an instrument, then selecting an effects plugin instead)
I choose the plugin for the latest (at the time) beta (pre 10.10 release) VST3x64.
I immediately go to Application Settings and open the skin settings to show the titlebar color number.
The number continually counts up until it needs to process mouse movement from the selection box and pauses for a second. I could have let this part go longer, but I had already shown the important parts.
Oh, can we also get this thread stickied and the old one unstickied?