I installed the update and ran my trousers through the fitting room again.

... Bending the thigh backwards and forwards is still a problem with the rigged pants, her butt pops out through the pants even in a normal sitting position. The glute deforms very strangely when bending the thigh backwards. Any set of ballet or figure skating poses for her would require additional morphs. Some people like their Poser figures to dance.

Have you tried adjusting the joint parameters on the pants? Sometimes this is necessary even after using the fitting room, depending on how far the clothing mesh sits from the figure mesh. Baggier clothing will require additional JP adjustments than tighter fitting clothing will. You can also create ERC adjustment morphs that will react to the leg bending in the areas where you're getting poke-thru. You can create those morphs inside PP2012 and 2014 with the morph brush and the parameters menu, without having to go into another modeling app.

Also, you can transfer morphs from the figure to the clothing via the figure menu > "Copy morphs from..." option. If you haven't already tried that of course.