I am using a background that has LOTS of arrows pointing down and to the right - with another arrow at the bottom pointing down and to the left. I put a box in the lower arrow and tilted it to match. Today I was going to change the text in that arrow - and it didn't show up.
I found that if the box is tilted in a way that puts PART of the box off the background (probably wrong term) that what was in the box doesn't show up/can't be changed. I had to move the box fully into the background area, and then the text showed up and I was able to change it.