I am trying to export my project as a VST3 Instrument on Windows (using Visual Studio 2022), but I am stuck with a GUI rendering issue.

The Problem: The export compiles successfully. When I load the VST3 in FL Studio, the audio works perfectly (I can hear the synth), but the GUI window is blank (it appears as a dark grey solid color). None of my interface controls (knobs/sliders) are visible. I tried the plugin on both Fl studio and Ableton and i get the same issue.