// add a listener to the grid and add the following lines
        this.on('rowcontextmenu',  function(grid, row, e) {
            grid.selectedNode = grid.store.getAt(row);  // we need this
            if((row) !== false) {
                this.getSelectionModel().selectRow(row);
            }            
            ... and the rest of your code ...

        }, this);

// add a listener to the grid and add the following lines
            listeners: {
                scope        : this,
                mousedown    : function(e, t, o) {
                    row = this.grid.view.findRowIndex(t)
                    if((row) !== false) {
                        this.grid.getSelectionModel().selectRow( row );
                    }
                },
                ... rest of your listeners ....
                
// don't forget the scope in the code above                

This refers to Ext JS version 3 !

Extjs - how to select a row in a grid with a right-mouse click

js, event

JavaScript