Since 1.5.19 some users noticed a malfunction with the Wikidata search box (top right corner).
Steps to reproduce:
* click on the search box
* type "test"
* the turning wheel icon appears, then disappears, and the suggestion drop-down doesn't show up
* when pressing the arrow down key or enter, it appears
Note: depending on the word that is typed, the menu seems to appear or not. "test" doesn't work, "foo" works.
Tested so far on Chrome and Firefox.