High cpu usage

[vkehayas]

When selecting a piece of text on any webpage while using Chromium (Version 45.0.2454.101 Ubuntu 14.04 (64-bit)) and the Fokus extension I get very high cpu usage, with all 8 cores staying at around 50% for as long as the text is selected. Is that the intended behaviour? Even with my relatively powerful machine this causes some perceptible lagginess.

System:
Ubuntu 14.04 LTS 64bit
3.13.0-71-generic #114-Ubuntu SMP Tue Dec 1 02:34:22 UTC 2015 x86_64
i7 @ 3.2 Ghz
24 GB RAM
GeForce GTX 560 Ti