That's not my problem. I am using the default configuration from Metronic, and that includes ngBootstrap. To summarize: I downloaded demo 1, perform the npm install, and without doing any custom changes, the toolbar does not work as expected.
Which could be the problem?
Besides, How can I access to my "6-month support" as a buyer?
You mentioned link is related to the HTML version of Metronic. (https://preview.keenthemes.com/metronic8/demo1/toolbars/saas.html). In the Angular version (also in all SPA versions React and Vue) we use standard HTML tag select+options for dropdowns. In the HTML version we use select2 library for dropdowns, which we don't use in SPA, cause it needs jQuery (we don't use jQuery in SPA apps).
Sorry, but that is a poor answer. Basically you are saying to clients that bought an elegant template that in some part raw HTML is used. The whole purpose of buying a template is not to work on the style. Raw HTML clearly goes against that principle.