The Parallel Gospel Reader tool has a wonderful capability to highlight the corresponding word in a different Gospel when I select a word in one Gospel.
However, sometimes it highlights words that are not actually in the other Gospels. Here is an example. When I hover over the Greek word ὅτε in Matthew 21:1 it properly highlights the same word in Mark 11:1. But it also highlights ὡς in Luke 19:28, which is clearly not the same word.

I suppose this is supposed to show when a different word is used in the same location within Gospel accounts. But is can be misleading, particularly in English where it is not clear if the difference is due to differences of translation rather than the original language words.