Save this to a .reg file and run it. This will overwrite your current registry settings.
Windows Registry Editor Version 5.00
[HKEY_CURRENT_USER\Software\GARMINCFMONITOR]
"left"="0"
"right"="0"
"top"="0"
"bottom"="0"
"zone2enable"="1"
"left2"="728"
"right2"="800"
"top2"="520"
"bottom2"="600"
"DEBUG"="0"
"TOOLTIPS"="0"
"GarminNavigatorWindowSizePosition"="0,50,800, 445"
"GarminNavigatorWindowSizePositionOSK"="0,50,800,4 45"
"ActivateOSK"="10,70,225,100"
"APPPATH"="C:\\Program Files\\Garmin\\GarminMobilePC\\Que.exe"
"APPNAME"="Garmin Mobile PC"
"APPWORKINGDIR"="C:\\Program Files\\Garmin\\GarminMobilePC"
You might need to adjust the path statement above to match your location, but everything else should work well.
All I did was download the Zero weight keyboard from here
http://www.freshnet8.com/ then I went into advanced settings on Centrafuse and then went into the General, then on the second page of the general settings, goto startup / shutdown commands and added the Zero weight keyboard application to startup, then it will ask you for any switches or other instructions.
Just type this in
quiet NoTapBox NoBumpBox largespacebar size=800x550x125% foreground=28 background=39 TypingTransparency=45
Then complete that part and exit CF. When you restart CF it will start the Zero weight keyboard in the background. Then when you're in GMPC and touch the Garmin name in the top left hand corner it will launch the Zero weight keyboard. When you're done, click hide in the top right hand corner.
I'm thinking of adjusting where you touch to get the keyboard to appear as it's easy to accidently move the application when you click, however when you click the CF button in the bottom right corner, then go back into GMPC it will reposition itself OK, but it's not ideal.
You can adjust where you click to make the keyboard appear by adjusting the line
"ActivateOSK"="10,70,225,100"
Just put the coordinates for where ever you want to make the active area, then re run the .reg file and the PC and it should move to where ever you've specified.
Hope that helps.
I had the exact same issue you did and it's because the coordinates you have to make the application hide are in the area you're trying to use......
I've got the above working on 3 cars and it's pretty good.