Plug-Ins allow you to use and position pre-defined modules into the right and left columns of the IMAS and IMAS Pro systems. "Active" toggles the Plug-In on/off. The "Plug-In" switch tells the system whether the code in that spot is a Plug-In or Widget. The pre-defined Plug-Ins are listed on the Help tab within IMAS/IMAS Pro.   The difference between a Widget vs a Plug-in is that a Widget  is a universal add-on with code obtained and/or designed outside the IMAS environment.  Widgets are not designed specifically for the IMAS systems but for general usage and isn't developed by the IMAS development group.  Where as a Plug-in is designed specifically for the IMAS systems by the IMAS development group.