@Override
	public boolean isValidAfter() {
		// check for permitted datatype
		if (newType instanceof FactoryDataType || newType.getLength() <= 0) {
			errorMsg = "Field of type '" + newType.getName() + "' - is not allowed.";
			return false;
		}
		if (hasSizeChange()) {
			int choice = OptionDialog.showOptionDialogWithCancelAsDefaultButton(null,
				"Increase the size of the union",
				"The size of the containing union will be changed if you continue.", "Continue",
				OptionDialog.WARNING_MESSAGE);
			if (choice != OptionDialog.OPTION_ONE) {
				return false;
			}
		}
		return true;
	}
@return true if the new field data-type will cause the size of the union to change
Ghidra/Features/Decompiler/src/main/java/ghidra/app/plugin/core/decompile/actions/RetypeUnionFieldTask.java