@Christoph-Hart I narrowed down the cause of the crashes. It has to with the code of the project. While it works in the stand-alone version, it crashes the plugin. I believe that this is part of the code that causes the crash:

settingsPanel.setContentData(channelData); settingsPanel2.setContentData(audioSettingsData); settingsPanel3.setContentData(midiInput);

@Jay It is how the pop-up panels are initiated. Get rid of that code and the project should open up.

I ended up rebuilding the entire project from scratch within the HISE plugin. I copied and pasted elements from standalone version and once I came across those elements, issues started to happen. I utilized different solution to display pop-ups, that Christoph provided in another post.