The following functions have a special meaning:

OnLoad():
   This function is called when the GUI script was loaded by GemRB.

StartTextScreen():
   This function is called when the engine encountered a TextScreen or an
   IncrementChapter game script action.

OpenWorldMapWindow():
   This function is called when the worldmap window must be opened.

UpdatePortraitWindow():
   This function is called when there was a change in the party, this includes
   party order and PC hitpoints or state changes that may affect portraits.

SelectionChanged():
   This function is called when there was a change in selection of a team member.

OpenStoreWindow():
   This function is called when the StartStore scripting action was called.
   Or a container item was accessed.

UpdateControlStatus():
   This function is called when a pane changed on the game screen.

OpenContinueMessageWindow():
   This function is called when the player may choose to continue a dialog.

OpenEndMessageWindow():
   This function is called when the player may choose to end a dialog.

DeathWindow():
   This function is called when the team/protagonist is killed. See also
   GameSetProtagonistMode().

OpenReformPartyWindow():
   This function is called when there are too many teammembers.

OpenContainerWindow():
   This function is called when the player accessed a ground pile or container.

CloseContainerWindow():
   This function is called when GemRB requests the container window to be closed.
