After revision#66971, SD_NOTEBOOK_TAB, SD_TOOL_BAR, SD_TAB_STUB, SD_TITLE_BAR's height is all base on system font height on Linux. But it's not changed on the fly when system font changed, you have to restart Eiffel Studio.
On Linux I have tested font sans 10, and font sans 20, the snapshots is attached. It works fine now. 
Thanks for your report.