1. Open page in page designer (for example Special Vendor List - from training What’s New for Microsoft Dynamics NAV 2009 Installation and Development -> CHAPTER 6: CREATE PAGES WITH PAGE DESIGNER -> Demonstration: Create a List Page
2. Create C/AL Global variable, name=MyArr (type = text30, Dimensions=3)
3. Select the field No. (1st field). In the Value field of the CaptionClass property enter: '3,'+MyArr
4. Select the field Description (2nd field). In the Value field of the CaptionClass property enter: '3,'+MyArr
5. Open C/AL Editor and put code “MyArr:=’Hello’;” to the onOpenPage trigger;
6. Create action, put code “CLEAR(MyArr);” to the onAction trigger.
7. Run for in RTC. The caption of 1st field is ‘Hello’, the caption of 2nd field is empty;
8. Run action (created at step 6). The caption of 1st field is its ID, the caption of 2nd field is still empty.
I suppose the behavior should be the same for both fields (they both should be empty).