[Bug] Grid fails to render when the Columns field contains just numbers

[TimonGeisbauer]

The Grid will not render if you define a Column with a Field like "any number/s".
It will print the following error msg to the console: "TypeError: this.colDef.field.indexOf is not a function"

use ::BBjGridExWidget/BBjGridExWidget.bbj::BBjGridExWidget
use ::BBjGridExWidget/GxColumns.bbj::GxColumn
use com.basiscomponents.db.ResultSet

sysgui! = BBjAPI().openSysGui("X0")
wnd! = sysgui!.addWindow(0,0,800,600,"GridExSample")
wnd!.setCallback(BBjAPI.ON_CLOSE,"byebye")

wnd!.setCallback(BBjAPI.ON_CLOSE,"byebye")
grid! = new BBjGridExWidget(wnd!,9876,0,0,wnd!.getWidth(),wnd!.getHeight())

c! = new GxColumn("1")
grid!.addColumn(c!)
c! = new GxColumn("2")
grid!.addColumn(c!)
c! = new GxColumn("3")
grid!.addColumn(c!)
c! = new GxColumn("4")
grid!.addColumn(c!)
c! = new GxColumn("5")
grid!.addColumn(c!)
c! = new GxColumn("6")
grid!.addColumn(c!)
c! = new GxColumn("7")
grid!.addColumn(c!)
c! = new GxColumn("8")
grid!.addColumn(c!)

grid!.setData(new ResultSet())

process_events

byebye:
bye