Just curious, why China did that, and why now. Is it related to Malaysia's oil exploration last year? I hope there is a good reason for this. If not, then it is not a good idea to stir the region, just when uncle sam want to rally them to go against China.
Anyway, it seems Malaysia has trouble in its Borneo part. First, the people over there seem tired of Malaysia rule that exploit their natural resources but give few back to the development of their territory. It seems there is a growing call for seccesionist. Secondly, the sultan in Philippine is also still demanding Malaysia to return the territory to them. There was even arm conflicts few years ago.
I think China should talk to these people.