In both versions 2.14 x86 and 2.16 x64, the Line Filters functionality appears to be broken. Even the simplest of filters such as ^# are not applied. Curiously, the documentation regarding the feature appears to be incorrect or out of date, as it describes a Save button in the LineFilters dialog tab which does not exist in either version; in these versions that capability seems to be accomplished by the check box to the left of each filter added. Though there is an Enable Line Filters check box in the dialog tab, I also looked for a global control in Options and could find none. It seems unlikely that this broken behavior is self-inflicted.
works for me.
Does it work even in a simple case like an attached file?
It seems that it was in a sense self-inflicted, through misunderstanding of the intended effect. I expected to see no highlighting at all for filtered - "ignored" - lines, but I have now realized because of your example that isn't the default behavior. I returned to the Colors options and changed the Ignored Differences colorations to white, and that produced the result I expected and desired.
Last edit: Mark Craig 2019-03-02