in src/main/java/idea/plugin/psiviewer/view/EditorPsiElementHighlighter.java [41:47]
void highlightElement(final PsiElement psiElement) {
ApplicationManager.getApplication().runReadAction(() -> apply(psiElement));
if (psiElement != null && psiElement.getReference() != null) {
ApplicationManager.getApplication().runReadAction(() -> applyReference(psiElement.getReference()));
}
}