I have been trying to get conditional formatting to work on a tab. I want it to change to be either yellow or blue depending on what is in a particular field. Any ideas???

I don't believe you can conditionally format the tab itself.

You can place buttons or fake-tabs over the real tabs and conditionally format those. The key is placement.

Not the entire tab itself. You will have to go with either faked tabs or something similar.

This is an idea...

( maybe you'll have to modify for Mac )

CondFormatTAB.zip

Don't know the FMP version, but if it's 9, you can make the real tabs 0 px width. Then make text boxes for the tabs, sized and placed however you want with Conditional Formatting. Make the box a button with the simple Go To Object command referencing the respective tab.