Many third-party aircrafts have their own set of keys assigned to different panels.

For example on default aircrafts, pressing SHIFT-3 will invoke the GPS panel.   But this key-combo is not necessarily able to call up the GPS panel on Carenado and Aerosoft aircrafts.

If one has assigned an external button, say button 3 on a Saitek FIP, for the GPS panel, the difference between the default and third-party aircraft panel key assignment therefore will be quite annoying when aircrafts are changed.

To standardize panel key assignments across different aircrafts:

1)
Open the panel.cfg file under the Panel folder of the specific aircraft

2)
Rearranging the order of Window definition as needed as illustrated below will do

NOTE:
Although this tweak generally applies to all third-party aircrafts, files and settings involved may be different from vendors to vendors.