scrollable is unnecessarily collapsing the current document selection

[Douglas Hays]

scrollable:addCover does a collapse of the window's selected text. This is breaking ComboBox which highlights the autocompleted text in a textbox that is unrelated to the touch/scroll DIV that is being scrolled/transformed. The collapse also hides the cursor from the ComboBox textbox.

[ykami]

The problem is not the cover, but the selection code at the end of addCover which destroys focus:

var sel;
if(dojo.global.getSelection){
        sel = dojo.global.getSelection();
        sel.collapse(dojo.doc.body, 0);
}else{
        sel = dojo.doc.selection.createRange();
        sel.setEndPoint("EndToStart", sel);
        sel.select();
}

It was basically for IE. IE unexpectedly makes selection when you try to do touch-scrolling. I found that setSelectable(this._cover, false); could prevent the selection. The above code in no longer necessary.

[ykami]

(In [24064]) Refs #12480 !strict. Used setSelectable(this._cover, false) instead of collapsing the selection.