Is your variable Wnd globally defined?
And why not do this...
js code:
// if a browser button is clicked
function OnWndBrowserEvent_CtrlClicked(objWnd, strControlId)
{
switch(strControlId)
{
case "BtnSearch": // if the search button is clicked
>>> SearchWnd = MsgPlus.CreateChildWnd(objWnd, "Windows.xml", "WndSearch", 100, 100);<<<
// creates a child window (parent = 'Wnd')
break;
}
}