Use the ScrollPartVisible property to add or remove buttons/parts in the control's scrollbar. By default, when a part becomes visible, the ScrollPartEnable property is automatically called, so the parts becomes enabled. Use the ScrollPartEnable property to specify enable or disable parts in the control's scrollbar. Use the ScrollBars property to specify the visible scrollbars in the control. Use the ScrolPartCaption property to specify the caption of the scroll's part. Use the OffsetChanged event to notify your application that the scroll position is changed. Use the OversizeChanged event to notify your application whether the range for a specified scroll bar is changed. Use the ScrollPos property to specify the position for the control's scroll bar. The control fires the ScrollButtonClick event when the user clicks a part of the scroll bar. Use the Background property to change the visual appearance for any part in the control's scroll bar. Use the ScrollOrderParts property to customize the order of the buttons in the scroll bar. 

By default, the following parts are shown:

• exLeftBPart ( the left or up button of the control )
• exLowerBackPart ( the part between the left/up button and the thumb part of the control )
• exThumbPart ( the thumb/scrollbox part )
• exUpperBackPart ( the part between the the thumb and the right/down button of the control )
• exRightBPart ( the right or down button of the control )

The following VB sample adds up and down additional buttons to the control's vertical scroll bar :

With Tree1
    .BeginUpdate
        .ScrollBars = exDisableBoth
        .ScrollPartVisible(exVScroll, exLeftB1Part Or exRightB1Part) = True
        .ScrollPartCaption(exVScroll, exLeftB1Part) = "<img></img>1"
        .ScrollPartCaption(exVScroll, exRightB1Part) = "<img></img>2"
    .EndUpdate
End With

The following VB.NET sample adds up and down additional buttons to the control's vertical scroll bar :

With AxTree1
    .BeginUpdate()
    .ScrollBars = EXTREELib.ScrollBarsEnum.exDisableBoth
    .set_ScrollPartVisible(EXTREELib.ScrollBarEnum.exVScroll, EXTREELib.ScrollPartEnum.exLeftB1Part Or EXTREELib.ScrollPartEnum.exRightB1Part, True)
    .set_ScrollPartCaption(EXTREELib.ScrollBarEnum.exVScroll, EXTREELib.ScrollPartEnum.exLeftB1Part, "<img></img>1")
    .set_ScrollPartCaption(EXTREELib.ScrollBarEnum.exVScroll, EXTREELib.ScrollPartEnum.exRightB1Part, "<img></img>2")
    .EndUpdate()
End With

The following C# sample adds up and down additional buttons to the control's vertical scroll bar :

axTree1.BeginUpdate();
axTree1.ScrollBars = EXTREELib.ScrollBarsEnum.exDisableBoth;
axTree1.set_ScrollPartVisible(EXTREELib.ScrollBarEnum.exVScroll, EXTREELib.ScrollPartEnum.exLeftB1Part | EXTREELib.ScrollPartEnum.exRightB1Part, true);
axTree1.set_ScrollPartCaption(EXTREELib.ScrollBarEnum.exVScroll, EXTREELib.ScrollPartEnum.exLeftB1Part , "<img></img>1");
axTree1.set_ScrollPartCaption(EXTREELib.ScrollBarEnum.exVScroll, EXTREELib.ScrollPartEnum.exRightB1Part, "<img></img>2");
axTree1.EndUpdate();

The following C++ sample adds up and down additional buttons to the control's vertical scroll bar :

m_tree.BeginUpdate();
m_tree.SetScrollBars( 15 /*exDisableBoth*/ );
m_tree.SetScrollPartVisible( 0 /*exVScroll*/, 32768  /*exLeftB1Part*/ | 32 /*exRightB1Part*/, TRUE );
m_tree.SetScrollPartCaption( 0 /*exVScroll*/, 32768  /*exLeftB1Part*/ , _T("<img></img>1") );
m_tree.SetScrollPartCaption( 0 /*exVScroll*/, 32 /*exRightB1Part*/ , _T("<img></img>2") );
m_tree.EndUpdate();

The following VFP sample adds up and down additional buttons to the control's vertical scroll bar :

With thisform.Tree1
    .BeginUpdate
        .ScrollBars = 15
        .ScrollPartVisible(0, bitor(32768,32)) = .t.
        .ScrollPartCaption(0,32768) = "<img></img>1"
        .ScrollPartCaption(0, 32) = "<img></img>2"
    .EndUpdate
EndWith

*** ActiveX Control Event ***
LPARAMETERS scrollpart

wait window nowait ltrim(str(scrollpart))