[Please note this tip is largely superseded by the Reference Activation options in the right-press context menu]
Here is another for V8i to Activate a Reference file by Data point
I added a Reference Activate and Reference Deactivate on my View bar menu
1st create a dglib file in your interface folder .
Then open the file Key in MDL load custmiz
Go to the 2d view control menu and insert a tool(s)
For the command keyin" t,reference activate;%d "
The %d allows you to pick the Reference file you want to activate by data point
You can do the same for deactivate reference
Of course you could also put this on a function key