Something odd going on here.
I have ESV open at Ex 2:10 and LHI open at the same passage, the latter with sympathetic highlighting selected (but switched off in ESV). I highlight "he looked this way and that" in ESV (Ex 2:12), and sure enough, the corresponding LHI text is highlighted.
But then I scroll down LHI a couple of mousewheel clicks and the LHI highlighting disappears, even though ESV text is still selected.
Now if I deselect the text in ESV, the sympathetic highlight reappears in LHI.
This is 100% reproducible.