Accessibility for rollOverCanvas in ListGrids

[shresthg_des]

SmartClient Version: v9.1p_2016-04-15/Pro Development Only (built 2016-04-15)
Google Chrome Version 43.0.2357.125 unknown (64-bit) (any browser)

We have a ListGrid defined with a rollOverCanvas but we want to have a certain tab navigation order. On a selected row, if the user presses the tab key to navigate, would it be possible to show and focus the rollOverCanvas? Or is there a shortcut key that allows us to show the rollOverCanvas when selected on a row?

isc.ListGrid.create({
    ID:"countryList",
    width:500, height:224,
    data: countryData,
    selectionType:"single",
    fields:[
        {name:"countryCode", title:"Flag", width:50, type:"image", imageURLPrefix:"flags/16/", imageURLSuffix:".png"},
        {name:"countryName", title:"Country"},
        {name:"capital", title:"Capital"},
        {name:"continent", title:"Continent"}
    ],
    showRollOverCanvas:true,
    showRollUnderCanvas:false, // disable the rollUnderCanvas because we're not using it
    rollOverCanvasConstructor:isc.HLayout,
    rollOverCanvasProperties:{
        snapTo:"TR", height:20, width:40,
        members:[
            {_constructor:"Button", title:"+", 
             click:"isc.say('Expanded record:' + this.echo(this.parentElement.record))", 
             height:20, width:20},
            {_constructor:"Button", title:"-", 
             click:"isc.say('Collapsed record:' + this.echo(this.parentElement.record))",
             height:20, width:20}
        ]
    }
});

[Isomorphic]

The rolloverCanvas is currently never made part of the tab order, and while it would theoretically be possible to add your own key handling to incorporate it, this is rather complicated. If you are just trying to fulfill accessibility guidelines we would instead recommend keyboard shortcuts equivalent to the buttons in the rolloverCanvas, or buttons external to the grid that act on the selection (your application could optionally make such buttons visible only in screenreader mode).