I had a similar issue ... I don't know if Lightheaded data files used to be load on demand, but what I had to do was the following:
- From the character select screen click the button "Addons" in the lower left.
- Scroll down and locate the Lightheaded A through E entries and select them.
- Save your changes and select your character.
This probably adds a little to the memory consumption because the modules are being forced to load at startup rather than as they are used, but it's a small price to pay in regards to having to have a browser open and flipping between screens.
Hope that helps.