private void OnBlendModeChanged(object sender, EventArgs e)
{
blendmode = UserBlendOps.GetBlendModeByName (blendComboBox.ActiveText);
PintaCore.Layers.CurrentLayer.BlendMode = blendmode;
if (PintaCore.Layers.SelectionLayer != null) {
//Update BlendMode for SelectionLayer and force redraw
PintaCore.Layers.SelectionLayer.BlendMode = PintaCore.Layers.CurrentLayer.BlendMode;
}
PintaCore.Workspace.Invalidate ();
}