Random sprites stucks in scene 'till i reopen unity(migrating from 2.6 to 3.0.1)

[nwsx]

here you can see how it looks like. i've tried to remove all ui objects from scene, it didnt help.
http://i011.radikal.ru/1310/f1/d0c15248e315.png

it dissapears if i restart unity, but appears again after i hit play.

also i have another problem. i have custom shader that scrolling alpha mask over texture.
but is stop working in 3.0.1, sprite just not getting updated. 

[nwsx]

as i can see it's somehow related with disabling certain UIPanels during gameplay

[ArenMook]

And also often related to not following upgrade instructions that involve creating a new scene and deleting the NGUI folder before importing the latest package.