About GuiModelessDialogProfile problem

I meet a problem about GuiModelessDialogProfile,I set my two Dialog window as GuiModelessDialogProfile,as a result,two Dialog windows can be choosed and focused and changed when my mouse click,but focused Dialog window can not be most front window,because some portion has been covered by the other Dialog window,I don't know how to realize this function like Microsoft window style choosed and clicked by mouse.Can GUYs help me to solve it?!!!

new GuiControl(aboutDlg) {
profile = "GuiModelessDialogProfile";//**set Modeless
setFirstResponder = "True";
//profile = "GuiDefaultProfile";
horizSizing = "right";
vertSizing = "bottom";
position = "0 0";
extent = "640 480";
minExtent = "8 8";
visible = "1";
helpTag = "0";


new GuiWindowCtrl() {
profile = "GuiWindowProfile";
horizSizing = "center";
vertSizing = "center";
position = "132 88";
extent = "376 303";
minExtent = "8 8";
visible = "1";
helpTag = "0";
text = "About...";
maxLength = "255";
resizeWidth = "0";
resizeHeight = "0";
canMove = "1";
canClose = "1";
canMinimize = "0";
canMaximize = "0";
minSize = "50 50";
closeCommand = "Canvas.popDialog(aboutDlg);";

new GuiMLTextCtrl(aboutText) {
profile = "GuiMLTextProfile";
horizSizing = "width";
vertSizing = "relative";
position = "19 36";
extent = "336 241";
minExtent = "8 8";
visible = "1";
helpTag = "0";
lineSpacing = "2";
allowColorChars = "0";
maxChars = "-1";
text = "This is a test";
};
new GuiButtonCtrl() {
profile = "GuiButtonProfile";
horizSizing = "right";
vertSizing = "bottom";
position = "303 268";
extent = "60 23";
minExtent = "8 8";
visible = "1";
command = "Canvas.popDialog(aboutDlg);";
helpTag = "0";
text = "OK";
};