Problem:
Text ruler disappears when you click outside the text frame.
Example:
1. Create a new graphics document.
2. Select the Text Tool and type in a letter.
3. Select the Text ruler from the Format/Rulers dialog menu.
4. Click outside the text frame.
* Notice that the ruler disappears (zoom in or zoom out and it reappears).
Explanation:
The ruler will try to draw flat when it is disabled, except in cases where the current document type is not known, in which case it will erase the tab well area. When you first display the ruler it knows what the current data set is and draws with the flattened button look. When you click out of the text frame it is in a transition state and just erases.