When multiple bins are open, to close them all at once instead of one by one.
Alt + Click on the triangle of an open bin.
To open all bins at one: Alt+click on a triangle.
Alt+click also works for the fixed and added effects in the Effect Controls Panel.
These videos are really solid, but if anyone is still confused, here's one more explanation of asset management from Adobe Certified Expert Jeff Sengstack of InfiniteSkills. If it seems basic, that's because it's targeted toward beginners:
If you have opened a 5.5 project in CS6 you may experience the project panel search filter to go gray and restrict availability.
Try to save and restart.
If this doesn't work, then try to start a new PProCS6 project and import the 5.5 one, be sure to select "Entire Project" at the dialog box.
Other people have noticed this too. It might be related to unindexed items - if Premiere Pro CS6 doesn't finish indexing the clips, it won't let you search. This is something that may require a bug report. See the link below.
Or, you might be running into the problem discussed in this forum thread: