In order to proceed, you need to ensure the Mouse Over Bookings (Hourline And All Trees) is turned ON
Toolbox > Miscellaneous > Mouse Over Bookings (Hourline And All Trees)
*This setting has to be checked in combination with the settings in the Toolbox > Settings tab > Projects Tree and ObjectsTree (Mouse Over Bookings)
Now, you can customize the information displayed in the yellow Booking mouseover.
Click on the Setup Booking Mouseover Info button in Toolbox > Settings > Server Setup.
In the next window click on available display options to move them into the Selected pane, where you can drag and drop to adjust the order of the items. Note: You can add up to three separator lines.