Issue: When running scenario, during scene changing desktop background pops up sometimes.

Solution: Create "transition scene" which will pre-load sources from next scene by using Z-order function.

It means that "transition scene" is required for each new scene which should appear on video wall.

Example case: We have 4x2 videowall and we need to show 2 sources on left and right side of videowall, after 30 seconds this sources should change to 2 other sources.

To do this we need to create 3 scenes where the second scene will be "transition scene".

1. First of all, we checked that "ForceZOrder" feature is switched on in Polywall Visualizer:

2. Open operator interface (Polywall Designer) and start creation of scenario.

3. Click on layout preset button in each scene and set "resizing within cubes" or "manual adjustment" mode:

4. Put the sources on the screen and resize as we need.

5. Set time to 28 sec for our first scene and create new one.

6. Dont forget to link the scenes. Set time to 2 sec for the second scene. You will understand why we set this time later.

7. Put 2 other sources, which we want to see in next scene with same size parameters as sources in scene 1.

8. Put 2 previous sources, which we had in scene 1 and resize them same way as in scene 1.

After all actions, scenario section should looks like that: 2 scenes, with same sources, but in scene 2 we have our new sources UNDER sources from scene 1.

9. Copy paste the scene 2 and set 30 sec time for it.

10. In scene 3 close the sources, which we are using in scene 1.

11. In scenario section we will see this picture:

First scene - 2 sources

Second scene - 2 new sources under old one

Third scene - 2 new sources

12. Save this scenario in schedule folder.

In the end you will have 3 scenes, but all people will see only 2 of them, because 2nd scene is working like prebuffer to scene number 3. 

P.S. Please be noted, that time for second scene you need to count by yourself, because it all depends from size of the sources in next scene you want to show. For example light picture can be preloaded in 1-2 sec, but 4k video may take more than 10 sec.

P.S.S. This solution will not work if next scene has other amount or size of sources.