Effects GUI

I’m new to Audacity.
What puzzles me is the graphic interface of the effects .ExampIe: I imported SIR VST convolution plugin, but its interface on Audacity is completely different from usual and I can’t use it.
It seems that all effects have the same graphic interface in Audacity.
Also, the Preview is limited to a few seconds in any effect I tried.
Any help appreciated, thank you.

You can reset this is Audacity 1.3.x but not in 1.2.x

It is accessed via: Edit>preferences>Audio I/O


VST support is not built into Audacity as standard because Steinberg places restrictions on the use of the VST SDK code, so VST support is implemented using the VST Enabler which is not yet able to display custom interfaces for plug-ins. Instead, it uses generic controls for all VST plug-ins.