Does that happen with all the plugins, or are there only specific plugins that respond like that.
Do you have Renoise opened Full Screen or in windowed mode? (this question regards both issue 1 and issue 2)
An answer for issue 2 could be that you need to rescan your plugin folders prior to look them up if you add plugins to your system while Renoise is running.
If the “Scan for new VST plugins at startup” chckbox is disabled in the vst/Misc preferences, you will need to do that after any newly added plugin.
I have tried both those methods and nothing seems to be changed… i cant use renoise in a complete fullscren mode, only maximized. Some plugins work properly and some keep bugging up, i dont really know why that happens.
You could always check if the plugins run in another host (or report that they worked if you already testedt this). I know AU’s are an issue sometimes and not only in Renoise.
Also know that you cannot run PPC plugins on Intel Macs (these will never show) so make sure you have the intel compiled plugins installed.
If you mention the plugin titles that are troublesome, there might be folks here around that can either confirm your observation and perhaps even advise you how to fix it if possible.
I have the same problem with my Macbook Air 2014 Mavericks setup.
And it happens this way only for bridged VSTi/AU such as Sampletank 2.5 or Purity. If I use the 64bit version of Z3TA 2+ it works fine.
Also when I use a VSTi/AU, the dock appears and most importantly, I have to click to get back on Renoise if I want the keyboard-made MIDI keyboard to work, it’s pretty annoying when it comes to workflow ^^’