static boolean isToolBarButton( Component c ) {
		return c.getParent() instanceof JToolBar ||
			(c instanceof AbstractButton && BUTTON_TYPE_TOOLBAR_BUTTON.equals( getButtonTypeStr( (AbstractButton) c ) ));
	}
Returns true if the button has an icon but no text,
or it does not have an icon and the text is either "..." or one character.
flatlaf-core/src/main/java/com/formdev/flatlaf/ui/FlatButtonUI.java