Reposition the Outline in CCustomButton in C++(CheckBox)

I am using the CCustomButton Checkbox to add a checkbox in my window. Now as the checkbox is selected certain outline is created around the checkbox which is out of shape as in the picture I have attached.

I want to align that outline according to the checkbox that is checkbox in the middle . I am not sure what function of CCustomButton I can use to do this.

Now that I have to reposition the outline for the checkbox. Here is my code:

checkbox.MoveWindow(left, top, cx*COL_APPY_W_PCNT, 20);

where COL_APPY_W_PCNT is Percentage Width of the Checkbox which is 4/100.

I am getting this now:

I think all of the parts except the left part of this outline is not in its position. Is there any way I can align them?