This is a litle complicated. There are several bugs.
In a screenplay scene, enter a line of action. Hit enter.
Enter another line of action.
Select both lines of text.
From the font drop down, select “MS Sans Serif” (any font, except Courier will do)
Selected text changes font to MS Sans Serif.
Bug 1: Script element display at bottom of the window still says Action
Unselect the text, click on one of the lines of action text
Bug 2: Script element display at bottom of the window now says “General Text”
Select both lines of action again: use the mouse to select from the top down. (direction matters)
Select “Action” from the script element menu.
Bug 3: The first line of text remains MS Sans Serif and marked as General Text
The font of the second line of action changes to Courier and the Script element display at bottom of the window says “Action”
If you select the two lines of text from the bottom up, then the first line changes, and the second one remains unchanged.