I see this text for a long time, but I’ve today understood that I can click it. I believed it is a label for already visible fields.

I think the colon “:” should be removed and maybe the indicator-down placed nearer of the text, in order to better understand it is a collapsible element and not a title.

Or maybe with a verb: “See advanced parameters”.

Or with a larger white space between this and next block.

I think the confusion comes from the "double function" of the bar which has been there since the original prototype: It's used for previewing (and removing) search terms while collapsed and it's used for expanding/collapsing the parameter fields (which is also nonstandard OOUI, as @Volker_E reminded us at the Hackathon). Maybe that functionality should also be visually split into two parts somehow.

@Pols12 thank you for your feedback. I think you are right about the colon. I removed it from my mocks except for the second one where i feel it's necessary. The indicator is in the standard position for OOUI elements. It would create an inconsistent interface if we were to move it to a different location. I hope the addition of verbs, as you suggested, will make it seem more actionable.

Two of them with tags when collapsed for reference. I can do that for any text if you have different wording you'd like me to try out.

@JStrodt_WMDE @Lea_WMDE any ideas or feedback regarding the wording?

One question: Would it be helpful or bad if the text changed, depending on collapse state and/or the existence of search terms? E.g. "Refine your search" when there are no terms shown (both in the collapsed state when coming to the page for the 1st time and in the expanded state), "Filter search by:" in the collapsed state when there are search terms. If we can have different texts, then the text could also be "Search for" in the preview mode.

@Charlie_WMDE I'm not sure about "Refine your search" and "Filter your search". To me, these both sound as if you would first need to search in the general search bar (i.e. the upper one) and would use the "refine" or "filter" fields merely as a second step to refine/filter whatever you typed in that upper bar. To me, especially "filter" evokes this notion, like in an online shop when you see all shoes at first and then filter out only the blue ones.
But in our case, you can search with advanced parameters without using the general search bar at all.

I guess this effect could be reduced a little by a less active wording, e.g. "refined search" instead of "refine your search", but I'm not 100 % convinced.

Other suggestions:

• Detailed search
• Specified search

@Lea_WMDE Any remarks?

Note about external consistency: “advanced search” is a common phrase (MediaWiki, Discourse, Phabricator, PhpBB…) maybe since Google has used it.

We are thinking about making an A/B-Test for the words:

• One version that is more a known title rather than a request to do something (which will probably be "advanced search" due to it being known as @Pols12 pointed out)
• One version that is a request (either filter search or refine search)

In theory it is really hard to balance if it is more important to make it explicit to users that they can do sth, or to assure them, that you don't need to search first.

Change 511002 had a related patch set uploaded (by Tonina Zhelyazkova; owner: Tonina Zhelyazkova):
[mediawiki/extensions/AdvancedSearch@master] Rename Aadvanced Search panel

https://gerrit.wikimedia.org/r/511002

Change 511002 merged by jenkins-bot:
[mediawiki/extensions/AdvancedSearch@master] Rename "Advanced parameters" panel to "Advanced search"

https://gerrit.wikimedia.org/r/511002