Maybe the first navigable item in your block has changed? Make sure it is on your content canvas.
Check whether the content canvas has at least one navigable item or check whether the block has no navigable item
The KEY_BLOCK has 2 navigable fields and a display only field. When I bring up the form, the tabular block is showing but the Key_Block is not. I navigate backwards into the last field in the key_block and that is when the block becomes visible. It does not stay visible at all times after I see it for the first time. I have not mapped out the exact circumstances where it disappears again. This seems to have become a problem after we moved to 11g. Any thoughts?