I have had many requests to modify the fields encapsulated within the Event Type and that is typically not an issue. There are three pieces of Meta Data which seem to be impossible to remove through the site interface, “All Day Event,” “Recurrence,” & “Workspace.” Although these fields can’t be removed through your site interface, you can hide 1 or all of these fields through SharePoint Designer.
Many of the sites I have worked on have requested a Calendar which allows the user to select “All Day Event” & “Recurrence,” but would like to have Workspace Removed. (We will remove it in this example)
How to Hide Workspace:
1. Open Designer
2. Under the sites tab, open the site where the Event Content Type Resides
3. Under Navigation, select “Content Types”
4. From the Content Types Tab, select the Event Type which needs to have Workspace hidden
a. You should now have a tab open with the name of your content type
5. Select “Edit Content Type Columns” under Customization
This is where it can be a bit tricky and you start to realize some of the quirks of SharePoint Designer.
When you select Workspace, there is not a dropdown arrow to select the Property Type from the combo box. This is extremely irritating, but you have to click 3-4 (typically) to the right of the Optional Dialog until you will be presented with the dropdown options
You can now select the Hidden Property! Save your content type and your updates should now be reflected in SharePoint!