I just want to add that this is a pretty serious problem from the translator’s POV. Programmers might think putting up a disruptive warning is a good thing, but this disrupts our thought process, taking us out of “flow” (not to mention a timeout of 3 seconds is unreasonable, especially when we’re typing template calls); so in addition to potentially causing user errors, the current way of presenting the warning can have the potential to cause translation errors.

Per T164306: There should be a longer wait before displaying `There is an uneven amount of parenthesis`, the timeout was 500 ms, then increased to 2000 ms, then decreased to 1000 ms again. Then there is additional delay from network latency and request processing in the backend.

I’d like to add that this one-second timeout applies after the last keystroke, so if you’re typing continuously, the warning won’t appear, only once you stop typing.

I would like to comment that non-Latin languages exist. In CJK languages input is typed via an IME. Even if we typed continuously (from our POV) the system wouldn’t see input as being continuous. This is essentially a form of Euro-centric discrimination.

It also doesn’t change the fact that disrupting the display takes us out of flow. Therefore if your goal is to have us type “continuously” (very unreasonable in the first place, since we need to think) having the display disrupted is counter-productive.

Not to mention this is also an accessibility issue. Not everyone types through a keyboard. Any response-time-based assumptions are ableist.

This issue of "UI elements move the block I'm typing in" has frustrated me before, too. The warnings can be helpful, especially in long blocks of text, but the way they appear/disappear can cause problems with mis-clicking on the $tvar variables and Discard changes button, as well as the Publish button.
I think either of the proposed changes/solutions in the Description would be great.

New data point: I was updating the page for the sound logo contest so the CAT was showing source text differences for the segment. I was typing a wikilink (therefore it took more than 3 seconds) and suddenly the segment disappeared.

I took me a few seconds to find where the segment was on the screen. What happened was the field for showing diffs turned out to be the same field for showing the warning. So when the warning is shown the diff is hidden, moving the segment up almost half a screen. This is just too disruptive to be of any use.

If we can’t make the warning stable we need to have the option to turn off the bracket matching; tbh the warning is not helpful at all (esp. for languages where parentheses need to be translated).

I never took time to report this issue, but it annoys me for years too.

As a quick fix, we could probably simply remove that “bracket warning” because there is no reason it is more useful for translations than for common wikitext, and there is no such “help” in Wikieditor. This would also solve a second issue: the “bracket warning” overrides the Updated Definition Aid.

We could also move it as an alert after pressing submit button.