Sorry you're experiencing this issue and thank you for submitting a bug report.
I can confirm the issue is happening on my end and will investigate. It looks like a regression in recent versions.
In the mean time, switching to Pinned mode (left pin icon) should let you move the tabs wherever you prefer.
I've isolated and fixed the issue. It will be included in the next version. Thanks again for the report.
Fixed in Peek v.1.3.3.
Customer support service by UserEcho