windows 7 sp1 64bit
Broken: 2.76 release 48f7dd6
the "Seams from islands" in UVs menu can't mark up edges as cyan color when select "Mark sharp" option at fist time
You know the edges with "mark sharp" will become in cyan color, and the "Seams from islands" can mark seams and sharp by the islands, but when you select "mark sharp" from this option at fist time( never mark edges sharp operate at before ), the edges have be marked sharp, but the edges color won't change, if you random select one edge and use "mark sharp" from Ctrl+E in 3d view, the color will be changed and all be correct.
sorry for my poor English, the same problem in blender 2.74, and test in factory setting