Bug in question is
[Bug #11460], "Switching project and class browser slowdown".
Steps to reproduce:
1. Have C::B as the active project, and the help-plugin as the other project in your workspace. The class browser tab should be in "active project's symbols" (switch to the "Symbols" tab and verify, then switch back to the projects tab). Under settings, editor, code completion, C++ parser, the parsing should include global includes. Wait... the parsing should *NOT* include global includes.
Now let's start the experiment.
2. Start the C::B app, and *wait* till parsing finishes (the debug messages should say "class browser updated").
3. Double-click on the Help-Plugin project, and then switch to the symbols tab.
You should see a 4-sec delay in the class browser appearing.