property Item.SelBackColor as Color
Specifies the background color of the item when it is selected.

TypeDescription
Color A Color expression that specifies the item's background color, when the item is selected/checked. The last 7 bits in the high significant byte of the color indicates the identifier of the skin being used. Use the Add method to add new skins to the control. If you need to remove the skin appearance from a part of the control you need to reset the last 7 bits in the high significant byte of the color being applied to the background's part.
The SelBackColor property specifies a different background color or a visual appearance for the item, when item is selected / checked. The BackColor property specifies the item's background color of the item.  The SelHotBackColor property specifies a different background color or a visual appearance for the item, when item is selected / checked, and the cursor hovers it. The HotBackColor property specifies a different background color or a visual appearance for the item, when the cursor hovers it. The Caption property indicates the item's caption to be shown on the item. You can use the <bgcolor> HTML tag in the Caption property to specify a different background color for parts of the caption.

How can I change the item's background/backcolor, when the item is selected/checked (check-box)?

VBA (MS Access, Excell...)

With Ribbon1
	With .Items
		With .Add("Check 1")
			.HotBackColor = RGB(255,255,255)
			.SelBackColor = RGB(255,0,0)
			.SelHotBackColor = RGB(255,0,0)
			.ShowCheckedAsSelected = 1
			.Checked = True
			.Check = True
		End With
		.Add("").ToString = "Check 2[typ=1][chk=0][show=1][bghot=RGB(255,255,255)][bgsel=RGB(255,0,0)][bgselhot=RGB(255,0,0)" & _
"]"
	End With
	.Refresh 
End With

VB6

With Ribbon1
	With .Items
		With .Add("Check 1")
			.HotBackColor = RGB(255,255,255)
			.SelBackColor = RGB(255,0,0)
			.SelHotBackColor = RGB(255,0,0)
			.ShowCheckedAsSelected = exDisplayItemHighlight
			.Checked = True
			.Check = True
		End With
		.Add("").ToString = "Check 2[typ=1][chk=0][show=1][bghot=RGB(255,255,255)][bgsel=RGB(255,0,0)][bgselhot=RGB(255,0,0)" & _
"]"
	End With
	.Refresh 
End With

VB.NET

With Exribbon1
	With .Items
		With .Add("Check 1")
			.HotBackColor = Color.FromArgb(255,255,255)
			.SelBackColor = Color.FromArgb(255,0,0)
			.SelHotBackColor = Color.FromArgb(255,0,0)
			.ShowCheckedAsSelected = exontrol.EXRIBBONLib.ShowCheckedAsSelectedEnum.exDisplayItemHighlight
			.Checked = True
			.Check = True
		End With
		.Add("").ToString = "Check 2[typ=1][chk=0][show=1][bghot=RGB(255,255,255)][bgsel=RGB(255,0,0)][bgselhot=RGB(255,0,0)" & _
"]"
	End With
	.Refresh()
End With

VB.NET for /COM

With AxRibbon1
	With .Items
		With .Add("Check 1")
			.HotBackColor = RGB(255,255,255)
			.SelBackColor = RGB(255,0,0)
			.SelHotBackColor = RGB(255,0,0)
			.ShowCheckedAsSelected = EXRIBBONLib.ShowCheckedAsSelectedEnum.exDisplayItemHighlight
			.Checked = True
			.Check = True
		End With
		.Add("").ToString = "Check 2[typ=1][chk=0][show=1][bghot=RGB(255,255,255)][bgsel=RGB(255,0,0)][bgselhot=RGB(255,0,0)" & _
"]"
	End With
	.Refresh()
End With

C++

/*
	Copy and paste the following directives to your header file as
	it defines the namespace 'EXRIBBONLib' for the library: 'ExRibbon 1.0 Control Library'

	#import <ExRibbon.dll>
	using namespace EXRIBBONLib;
*/
EXRIBBONLib::IRibbonPtr spRibbon1 = GetDlgItem(IDC_RIBBON1)->GetControlUnknown();
EXRIBBONLib::IItemsPtr var_Items = spRibbon1->GetItems();
	EXRIBBONLib::IItemPtr var_Item = var_Items->Add(L"Check 1",vtMissing,vtMissing);
		var_Item->PutHotBackColor(RGB(255,255,255));
		var_Item->PutSelBackColor(RGB(255,0,0));
		var_Item->PutSelHotBackColor(RGB(255,0,0));
		var_Item->PutShowCheckedAsSelected(EXRIBBONLib::exDisplayItemHighlight);
		var_Item->PutChecked(VARIANT_TRUE);
		var_Item->PutCheck(VARIANT_TRUE);
	var_Items->Add(L"",vtMissing,vtMissing)->PutToString(_bstr_t("Check 2[typ=1][chk=0][show=1][bghot=RGB(255,255,255)][bgsel=RGB(255,0,0)][bgselhot=RGB(255,0,0)") +
"]");
spRibbon1->Refresh();

C++ Builder

Exribbonlib_tlb::IItemsPtr var_Items = Ribbon1->Items;
	Exribbonlib_tlb::IItemPtr var_Item = var_Items->Add(L"Check 1",TNoParam(),TNoParam());
		var_Item->HotBackColor = RGB(255,255,255);
		var_Item->SelBackColor = RGB(255,0,0);
		var_Item->SelHotBackColor = RGB(255,0,0);
		var_Item->ShowCheckedAsSelected = Exribbonlib_tlb::ShowCheckedAsSelectedEnum::exDisplayItemHighlight;
		var_Item->Checked = true;
		var_Item->Check = true;
	var_Items->Add(L"",TNoParam(),TNoParam())->ToString = TVariant(String("Check 2[typ=1][chk=0][show=1][bghot=RGB(255,255,255)][bgsel=RGB(255,0,0)][bgselhot=RGB(255,0,0)") +
"]");
Ribbon1->Refresh();

C#

exontrol.EXRIBBONLib.Items var_Items = exribbon1.Items;
	exontrol.EXRIBBONLib.Item var_Item = var_Items.Add("Check 1",null,null);
		var_Item.HotBackColor = Color.FromArgb(255,255,255);
		var_Item.SelBackColor = Color.FromArgb(255,0,0);
		var_Item.SelHotBackColor = Color.FromArgb(255,0,0);
		var_Item.ShowCheckedAsSelected = exontrol.EXRIBBONLib.ShowCheckedAsSelectedEnum.exDisplayItemHighlight;
		var_Item.Checked = true;
		var_Item.Check = true;
	var_Items.Add("",null,null).ToString = "Check 2[typ=1][chk=0][show=1][bghot=RGB(255,255,255)][bgsel=RGB(255,0,0)][bgselhot=RGB(255,0,0)" +
"]";
exribbon1.Refresh();

JScript/JavaScript

<BODY onload='Init()'>
<OBJECT CLASSID="clsid:DDF58CFA-750F-45E0-8A00-CFBE431702E2" id="Ribbon1"></OBJECT>

<SCRIPT LANGUAGE="JScript">
function Init()
{
	var var_Items = Ribbon1.Items;
		var var_Item = var_Items.Add("Check 1",null,null);
			var_Item.HotBackColor = 16777215;
			var_Item.SelBackColor = 255;
			var_Item.SelHotBackColor = 255;
			var_Item.ShowCheckedAsSelected = 1;
			var_Item.Checked = true;
			var_Item.Check = true;
		var_Items.Add("",null,null).ToString = "Check 2[typ=1][chk=0][show=1][bghot=RGB(255,255,255)][bgsel=RGB(255,0,0)][bgselhot=RGB(255,0,0)" +
	"]";
	Ribbon1.Refresh();
}
</SCRIPT>
</BODY>

VBScript

<BODY onload='Init()'>
<OBJECT CLASSID="clsid:DDF58CFA-750F-45E0-8A00-CFBE431702E2" id="Ribbon1"></OBJECT>

<SCRIPT LANGUAGE="VBScript">
Function Init()
	With Ribbon1
		With .Items
			With .Add("Check 1")
				.HotBackColor = RGB(255,255,255)
				.SelBackColor = RGB(255,0,0)
				.SelHotBackColor = RGB(255,0,0)
				.ShowCheckedAsSelected = 1
				.Checked = True
				.Check = True
			End With
			.Add("").ToString = "Check 2[typ=1][chk=0][show=1][bghot=RGB(255,255,255)][bgsel=RGB(255,0,0)][bgselhot=RGB(255,0,0)" & _
	"]"
		End With
		.Refresh 
	End With
End Function
</SCRIPT>
</BODY>

C# for /COM

EXRIBBONLib.Items var_Items = axRibbon1.Items;
	EXRIBBONLib.Item var_Item = var_Items.Add("Check 1",null,null);
		var_Item.HotBackColor = (uint)ColorTranslator.ToWin32(Color.FromArgb(255,255,255));
		var_Item.SelBackColor = (uint)ColorTranslator.ToWin32(Color.FromArgb(255,0,0));
		var_Item.SelHotBackColor = (uint)ColorTranslator.ToWin32(Color.FromArgb(255,0,0));
		var_Item.ShowCheckedAsSelected = EXRIBBONLib.ShowCheckedAsSelectedEnum.exDisplayItemHighlight;
		var_Item.Checked = true;
		var_Item.Check = true;
	var_Items.Add("",null,null).ToString = "Check 2[typ=1][chk=0][show=1][bghot=RGB(255,255,255)][bgsel=RGB(255,0,0)][bgselhot=RGB(255,0,0)" +
"]";
axRibbon1.Refresh();

X++ (Dynamics Ax 2009)

public void init()
{
	COM com_Item,com_Item1,com_Items;
	anytype var_Item,var_Item1,var_Items;
	str var_s;
	;

	super();

	var_Items = exribbon1.Items(); com_Items = var_Items;
		var_Item = com_Items.Add("Check 1"); com_Item = var_Item;
			com_Item.HotBackColor(WinApi::RGB2int(255,255,255));
			com_Item.SelBackColor(WinApi::RGB2int(255,0,0));
			com_Item.SelHotBackColor(WinApi::RGB2int(255,0,0));
			com_Item.ShowCheckedAsSelected(1/*exDisplayItemHighlight*/);
			com_Item.Checked(true);
			com_Item.Check(true);
		var_Item1 = COM::createFromObject(com_Items.Add("")); com_Item1 = var_Item1;
		var_s = "Check 2[typ=1][chk=0][show=1][bghot=RGB(255,255,255)][bgsel=RGB(255,0,0)][bgselhot=RGB(255,0,0)]";
		com_Item1.ToString(var_s);
	exribbon1.Refresh();
}

Delphi 8 (.NET only)

with AxRibbon1 do
begin
	with Items do
	begin
		with Add('Check 1',Nil,Nil) do
		begin
			HotBackColor := $ffffff;
			SelBackColor := $ff;
			SelHotBackColor := $ff;
			ShowCheckedAsSelected := EXRIBBONLib.ShowCheckedAsSelectedEnum.exDisplayItemHighlight;
			Checked := True;
			Check := True;
		end;
		Add('',Nil,Nil).ToString := 'Check 2[typ=1][chk=0][show=1][bghot=RGB(255,255,255)][bgsel=RGB(255,0,0)][bgselhot=RGB(255,0,0)]' + 
	'';
	end;
	Refresh();
end

Delphi (standard)

with Ribbon1 do
begin
	with Items do
	begin
		with Add('Check 1',Null,Null) do
		begin
			HotBackColor := $ffffff;
			SelBackColor := $ff;
			SelHotBackColor := $ff;
			ShowCheckedAsSelected := EXRIBBONLib_TLB.exDisplayItemHighlight;
			Checked := True;
			Check := True;
		end;
		Add('',Null,Null).ToString := 'Check 2[typ=1][chk=0][show=1][bghot=RGB(255,255,255)][bgsel=RGB(255,0,0)][bgselhot=RGB(255,0,0)]' + 
	'';
	end;
	Refresh();
end

VFP

with thisform.Ribbon1
	with .Items
		with .Add("Check 1")
			.HotBackColor = RGB(255,255,255)
			.SelBackColor = RGB(255,0,0)
			.SelHotBackColor = RGB(255,0,0)
			.ShowCheckedAsSelected = 1
			.Checked = .T.
			.Check = .T.
		endwith
		var_s = "Check 2[typ=1][chk=0][show=1][bghot=RGB(255,255,255)][bgsel=RGB(255,0,0)][bgselhot=RGB(255,0,0)]"
		.Add("").ToString = var_s
	endwith
	.Refresh
endwith

dBASE Plus

local oRibbon,var_Item,var_Item1,var_Items

oRibbon = form.Activex1.nativeObject
var_Items = oRibbon.Items
	var_Item = var_Items.Add("Check 1")
		var_Item.HotBackColor = 0xffffff
		var_Item.SelBackColor = 0xff
		var_Item.SelHotBackColor = 0xff
		var_Item.ShowCheckedAsSelected = 1
		var_Item.Checked = true
		var_Item.Check = true
	// var_Items.Add("").ToString = "Check 2[typ=1][chk=0][show=1][bghot=RGB(255,255,255)][bgsel=RGB(255,0,0)][bgselhot=RGB(255,0,0)]"
	var_Item1 = var_Items.Add("")
	with (oRibbon)
		TemplateDef = [Dim var_Item1]
		TemplateDef = var_Item1
		Template = [var_Item1.ToString = "Check 2[typ=1][chk=0][show=1][bghot=RGB(255,255,255)][bgsel=RGB(255,0,0)][bgselhot=RGB(255,0,0)]"]
	endwith
oRibbon.Refresh()

XBasic (Alpha Five)

Dim oRibbon as P
Dim var_Item as P
Dim var_Item1 as P
Dim var_Items as P

oRibbon = topparent:CONTROL_ACTIVEX1.activex
var_Items = oRibbon.Items
	var_Item = var_Items.Add("Check 1")
		var_Item.HotBackColor = 16777215
		var_Item.SelBackColor = 255
		var_Item.SelHotBackColor = 255
		var_Item.ShowCheckedAsSelected = 1
		var_Item.Checked = .t.
		var_Item.Check = .t.
	' var_Items.Add("").ToString = "Check 2[typ=1][chk=0][show=1][bghot=RGB(255,255,255)][bgsel=RGB(255,0,0)][bgselhot=RGB(255,0,0)]"
	var_Item1 = var_Items.Add("")
	oRibbon.TemplateDef = "Dim var_Item1"
	oRibbon.TemplateDef = var_Item1
	oRibbon.Template = "var_Item1.ToString = \"Check 2[typ=1][chk=0][show=1][bghot=RGB(255,255,255)][bgsel=RGB(255,0,0)][bgselhot=RGB(255,0,0)]\""

oRibbon.Refresh()

Visual Objects

local var_Item as IItem
local var_Items as IItems

var_Items := oDCOCX_Exontrol1:Items
	var_Item := var_Items:Add("Check 1",nil,nil)
		var_Item:HotBackColor := RGB(255,255,255)
		var_Item:SelBackColor := RGB(255,0,0)
		var_Item:SelHotBackColor := RGB(255,0,0)
		var_Item:ShowCheckedAsSelected := exDisplayItemHighlight
		var_Item:Checked := true
		var_Item:Check := true
	var_Items:Add("",nil,nil):ToString := "Check 2[typ=1][chk=0][show=1][bghot=RGB(255,255,255)][bgsel=RGB(255,0,0)][bgselhot=RGB(255,0,0)]"
oDCOCX_Exontrol1:Refresh()

PowerBuilder

OleObject oRibbon,var_Item,var_Items

oRibbon = ole_1.Object
var_Items = oRibbon.Items
	var_Item = var_Items.Add("Check 1")
		var_Item.HotBackColor = RGB(255,255,255)
		var_Item.SelBackColor = RGB(255,0,0)
		var_Item.SelHotBackColor = RGB(255,0,0)
		var_Item.ShowCheckedAsSelected = 1
		var_Item.Checked = true
		var_Item.Check = true
	var_Items.Add("").ToString = "Check 2[typ=1][chk=0][show=1][bghot=RGB(255,255,255)][bgsel=RGB(255,0,0)][bgselhot=RGB(255,0,0)]"
oRibbon.Refresh()

Visual DataFlex

Procedure OnCreate
	Forward Send OnCreate
	Variant voItems
	Get ComItems to voItems
	Handle hoItems
	Get Create (RefClass(cComItems)) to hoItems
	Set pvComObject of hoItems to voItems
		Variant voItem
		Get ComAdd of hoItems "Check 1" Nothing Nothing to voItem
		Handle hoItem
		Get Create (RefClass(cComItem)) to hoItem
		Set pvComObject of hoItem to voItem
			Set ComHotBackColor of hoItem to (RGB(255,255,255))
			Set ComSelBackColor of hoItem to (RGB(255,0,0))
			Set ComSelHotBackColor of hoItem to (RGB(255,0,0))
			Set ComShowCheckedAsSelected of hoItem to OLEexDisplayItemHighlight
			Set ComChecked of hoItem to True
			Set ComCheck of hoItem to True
		Send Destroy to hoItem
		Variant voItem1
		Get ComAdd of hoItems "" Nothing Nothing to voItem1
		Handle hoItem1
		Get Create (RefClass(cComItem)) to hoItem1
		Set pvComObject of hoItem1 to voItem1
			Set ComToString of hoItem1 to "Check 2[typ=1][chk=0][show=1][bghot=RGB(255,255,255)][bgsel=RGB(255,0,0)][bgselhot=RGB(255,0,0)]"
		Send Destroy to hoItem1
	Send Destroy to hoItems
	Send ComRefresh
End_Procedure

XBase++

#include "AppEvent.ch"
#include "ActiveX.ch"

PROCEDURE Main
 	LOCAL oForm
	LOCAL nEvent := 0, mp1 := NIL, mp2 := NIL, oXbp := NIL
	LOCAL oItem
	LOCAL oItems
	LOCAL oRibbon

	oForm := XbpDialog():new( AppDesktop() )
	oForm:drawingArea:clipChildren := .T.
	oForm:create( ,,{100,100}, {640,480},, .F. )
	oForm:close  := {|| PostAppEvent( xbeP_Quit )}

	oRibbon := XbpActiveXControl():new( oForm:drawingArea )
	oRibbon:CLSID  := "Exontrol.Ribbon.1" /*{DDF58CFA-750F-45E0-8A00-CFBE431702E2}*/
	oRibbon:create(,, {10,60},{610,370} )

		oItems := oRibbon:Items()
			oItem := oItems:Add("Check 1")
				oItem:SetProperty("HotBackColor",AutomationTranslateColor( GraMakeRGBColor  ( { 255,255,255 } )  , .F. ))
				oItem:SetProperty("SelBackColor",AutomationTranslateColor( GraMakeRGBColor  ( { 255,0,0 } )  , .F. ))
				oItem:SetProperty("SelHotBackColor",AutomationTranslateColor( GraMakeRGBColor  ( { 255,0,0 } )  , .F. ))
				oItem:ShowCheckedAsSelected := 1/*exDisplayItemHighlight*/
				oItem:Checked := .T.
				oItem:Check := .T.
			oItems:Add(""):ToString := "Check 2[typ=1][chk=0][show=1][bghot=RGB(255,255,255)][bgsel=RGB(255,0,0)][bgselhot=RGB(255,0,0)]"
		oRibbon:Refresh()

	oForm:Show()
	DO WHILE nEvent != xbeP_Quit
		nEvent := AppEvent( @mp1, @mp2, @oXbp )
		oXbp:handleEvent( nEvent, mp1, mp2 )
	ENDDO 
RETURN