Is the Plugin Window offscreen? I know that if I drag my plugin Window down to the bottom of my screen (so only the very top edge is showing) I sometimes think the plugs aren't opening when I click on them in the bin but they are just kind of hiding. If I drag them back into view there they are.
Also remember that in SPlat we now have Plugin Window Recycling so instead of a bunch of plugins popping up they pop up into the same window (and the previous one disappears). This behavior can be disabled in Preferences and/or you can use the "Pin Plugin Window" option to have multiple plugin GUIs open on screen at once.
Cheers and welcome to the forum.