In that case run the SYS:Prefs/MCPPrefs, switch to Hotkeys tab, select Active Window under MousePointer, press the Definition button, change the Mouse entry to eg. DoubleClick, press the upper Sample button and click once with your left mouse button. This way you tell the program to use the left mouse button for this operation.
Please do the same with Active Window to Front entry in Hotkeys tab.
Now save the settings and reboot AmiKit. The windows should be bring to front by doublecliking them.