You can lock the style you are working on and change its properties to get an immediate preview, without the need to switch between styles. Create a multilayered style on your image, with chained styles on each layer.

Lock the Preview

Select the layer  that has the preview that you want to keep visible (In our exemple : "Random Painter/Great Times/Texturize"). Click the Lock icon to lock the preview. The entire layer will be locked in the preview.

Select the style which has the properties you want to modify (e.g. "Random Painter") and drag the sliders in the “Properties + Preview” pane.  The preview you have locked previously will be rendered in real time a nd a Progress Bar will show the elapsed processing time.

Change the style's properties as many times as you want, the preview will be rendered again.