I Have an assembly, with about 150 odd parts, and a hand full of sub assemblies,

sometimes when I open the odd random part\drawing a dozen or so other parts\subs open as well, there is no direct link between the parts (some of these parts may be linked to a common sub assembly) but some of the parts\subs that open are totally unrelated.. apart from mates..

is there a tick box some were to stop this from happening, at times it can bog my system down by just opening a part or its drawing?