Node selection in some pop ups

It's now possible to switch nodes in pop ups where it shouldn't be available, for instance, in the item prototype selection pop up when configuring an trigger or graph prototype.

Broken in:

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r37271 | eduards | 2013-07-24 17:07:05 +0300 (Wed, 24 Jul 2013) | 1 line

..F....... ZBX-6706 fixed nodes display
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