void () { myFixture.configureByText(PlainTextFileType.INSTANCE, " "); class CustomHandler implements ParameterInfoHandler<PsiElement, Object>, DumbAware { @NotNull @Override public PsiElement findElementForParameterInfo(@NotNull CreateParameterInfoContext context) { context.setItemsToShow(new Object[]{this}); return context.getFile(); } @Override public void showParameterInfo(@NotNull PsiElement element, @NotNull CreateParameterInfoContext context) { context.showHint(context.getFile(), context.getOffset(), this); } @NotNull @Override public PsiElement findElementForUpdatingParameterInfo(@NotNull UpdateParameterInfoContext context) { return context.getFile(); } @Override public void updateParameterInfo(@NotNull PsiElement o, @NotNull UpdateParameterInfoContext context) {} @Override public void updateUI(Object p, @NotNull ParameterInfoUIContext context) { context.setupUIComponentPresentation("<ABC>, DEF", 7, 10, true, true, false, context.getDefaultParameterColor()); } } LanguageParameterInfo.INSTANCE.addExplicitExtension(PlainTextLanguage.INSTANCE, new CustomHandler(), getTestRootDisposable()); showParameterInfo(); checkHintContents("<html><strike>&lt;ABC&gt;, <b>DEF</b></strike></html>"); }