This was originally meant to become UpgradesGUI Continued, but for several reasons starting "from scratch" proved more practical, and this Add-On inherited only a little from the former by @Gotmachine. For now it remains more limited than UpgradesGUI in certain ways.
This plugin works in the VAB or SPH and adds a button to the right-click menu on any parts with upgrades to expand their applications and allow for implementing upgrades as alternatives which can be chosen at any time, regardle
Version 0.3.4:
https://drive.google.com/open?id=1Cm5WA73G3IEONZ-JjEXQC0ULmpUA3Og1
This version should have been the first one for public release, because besides not having yet a decent setup to support part symmetry(there are ways to deal with limitations in the support for part symmetry though, see the Readme for details), all major issues that could be identified and reproduced were fixed now.
Letting the issue with ModuleRCS and RCSFX slide was a big mistake, but it's solved n