Call function when a Component is selected

Hello

I am trying to add some custom functionality to the MUI2 Components Page.

When the user selects a Component(Checkbox) I want to call my custom function. If the 1st component has bee selected then I want to check/select the 2nd component also.

My code below attempts to code this functionality but I am getting compile errors:

Error in macro __NSD_OnControlEvent on macroline 8

!include nsdialogs.nsh

	!include MUI2.nsh



	!define MUI_PAGE_CUSTOMFUNCTION_SHOW compshow



	!insertmacro MUI_PAGE_COMPONENTS

	!insertmacro MUI_PAGE_INSTFILES

	!insertmacro MUI_LANGUAGE "English"



	OutFile "test.exe"



	Function OnCustomisationComponentClick 

		#SendMessage 1032 ${TVM_SETITEM} 0 $someTVItem

		MessageBox MB_OK "abc"

	FunctionEnd



	Function compshow

		FindWindow $0 "#32770" "" $HWNDPARENT

		GetDlgItem $0 $0 1032 # 1032 is the Treeview that holds the components

		!insertmacro __NSD_OnControlEvent ${TVM_SELECTITEM} $0 OnCustomisationComponentClick

	FunctionEnd





	Section "Dummy"



	SectionEnd