(I tried to post this to the bug tracker on themes.tiki.org, but I couldn't make a new post even after logging in.)
In the Coelesce theme, The search module has problems when placed in the left sidebar. This worked in version 9.0, problem is in 10.2. I don't know about versions in between. Verified on demo site.
1. The text entry field is not visible until clicked on. Also, it doesn't look like the one in the search_wiki_page module.
2. The advanced search label and check box, the search help label and button, and the Go button, are positioned to the right of the text entry field and are therefore pushed out over the page content. They should be under the text entry field. This can be fixed by changing line 370 of the coelesce.css file. This line currently says "white-space: nowrap;" Change "nowrap" to "normal". I don't know what this change will do in other situations.
I also noticed that the html is very different between this module and the search_wiki_page module. I would think they should be more similar.