With panel2 try setting the left anchor to Panel1 and set your space on the left side to 10 too.
Remove the right anchor of Panel1 that is trying to anchor to Panel2.
It maybe that the default position of Panel2 is more to the right in windows and in Linux it is
closer to panel1. This could be some issue with scaling etc.
I've always tried to anchor going left to right, so that each control has it's LEFT anchor set to the previous
control. The last control to the right can then anchor itself to the form or in your case the tabsheet.