I'm currently re-designing FFS's Saab 320 panel and like to have a popup MFD which opens with the corresponding button.
While the MFD works when it's added to [window00], the popup variant (which perfectly opens when clicking the "open MFD" button) is completely black and "dead"!
I tested with popup only as well as a gauge on the main panel together with the popup, each time the same result (in the latter case, the gauge in [window00] clears as intended, but the popup is "clear" as well).
You need to use the 'WN' name as the 5th parameter for gauges that are in a popup window.
If you have the EHSI or EADI gauge in [window00] and in a popup window, use the 'ident' for that gauge in the popup window.
This will allow the popup window to toggle open when you click on the hot area in the center of the EADI or EHSI. Or when you click on the icon button to open the popup window.
Below is the list of idents for all the gauges.
If the gauge is in the Virtual cockpit use the 'VC' parameter.
If you have more than one instance of the EHSI or the MFD in the virtual cockpit, use the 'VC2' parameter on the 2nd instance.
An example would be a Virtual cockpit with the gauge installed on the pilot and co-pilot sides, if the panel is centered on the pilot (left) side
then you won't really be reading the gauge on the co-pilot side. The VC2 parameter turns off some frame rate intensive features (like the ATC boundary display) on the second instance to lessen the frame impact of both gauges displaying at the same time in the VC. But the VC2 gauge will still appear to working in the Virtual cockpit.
For more details see the 'settings' document.