Dear ImGui already uses such "implicit" widget ids, by default it hashes the widget's label string, window title or name, with a convention to add an invisible 'identifier string' to the label string separated by a "##" (e.g. "Label##id") - for the case that the visible label string needs to change or isn't unique within the current scope. There are also separate PushID/PopID functions to manage such widget ids in "more elaborate ways".