Cannot select 'record type' when you create Activities from the Activity list view in Classic

Workaround: Create a Custom Button for Record Type Selection

As a workaround, you can replace the standard "New Event" or "New Task" button with a custom button that prompts for record type selection and place it on the Activities list view.

Step 1: Create the Custom Button

1. Go to:
   1. Classic: Setup | Customize | Activities
   2. Lightning: Setup | Object Manager | Select Task or Event | Buttons, Links and Actions
2. For Tasks: Select Task Buttons, Links, and Actions. For Events: Select Event Buttons and Links.
3. Click New Button or Link. Add a Label and Name. For Display Type, select List Button. Choose Behavior and set Content Source to URL.
4. Add the following syntax:
   1. For New Event: /setup/ui/recordtypeselect.jsp?ent=Event&retURL=%2Fhome%2Fhome.jsp&save_new_url=%2F00T%2Fe%3FretURL%3D%252Fhome%252Fhome.jsp
   2. For New Task: /setup/ui/recordtypeselect.jsp?ent=Task&retURL=%2Fhome%2Fhome.jsp&save_new_url=%2F00T%2Fe%3FretURL%3D%252Fhome%252Fhome.jsp
5. Click Save.

Step 2: Add the Button to the Activity List View

1. Go to:
   1. Classic: Setup | Customize | Activities
   2. Lightning: Setup | Object Manager | Select Task or Event
2. Select Activity Search Layouts.
3. Click Edit on the Activity list view.
4. Remove the standard buttons and add the custom button you created.
5. Click Save.