From your video, I see the taskbar icons get shrink down a bit since your taskbar is at almost full with pinned item. So when you launch an application, Start11 try to make space for that application. Perhaps, try to cut down on pinned apps on your taskbar and use your Start panel to pinned application. Start11v2 come with tabs so you can pinned more applications on it.
Just as a suggestion, here what my taskbar and Start panel look like,
Thank you,
Basj,
Stardock Community Assistant
