1. Run the attached test.
2. Start typing the characters until it becomes five lines and you get output similar to screen1.png. At this stage textbox has maximum lines (5) which can be visible by default and any more lines will make the scrollbar visible.
3. Add more characters to make it 6 lines - see screen2.png
4. Now start deleting some characters from end and make it again 5 lines so that the content in the textbox is same as step 2 (in my screenshots the content visible in both the cases is till fifth-5 line).
5. At this stage scrollbar disappears though there is content which can be scrolled and user has to see the content using arrow keys.

I would expect that output in step2 and step 4 should be same so that when scrollbar is not required because content can fit to visible area of textbox by default, then whole content should also become visible similar to what happens when we start in step2. Or the scrollbar shouldn't become invisible (contrary to MOBL-1382). Better approach should be taken.