Conditional formatting not being applied to all drop-down lists

Hi.

I hope this is a fairly simple question to answer...

Updated question: How do I apply conditional formatting to an entire workbook?

Original question: I have an Excel 2010 workbook with multiple sheets and on each sheet there are multiple cells that use:-

Data Validation > List > Source ='Drop-down lists'!$A$3:$A$7

I've created conditional formatting to change the format of the cell depending on which item from the drop-down is selected. This is working fine but only on the one cell that was selected when I created the formatting.

The formatting rule is as follows:-

Format only cells that contain > Cell value > Equal to > ='Drop-down lists'!$A$5

How do I make all of the cells that are using 'Drop-down lists'!$A$5 in the workbook apply the same formatting?

I've attached the workbook to this post

Thanks.