Last modified: 2014-02-20 21:26:52 UTC
Quoting from https://www.wikidata.org/wiki/Wikidata:Contact_the_development_team#Tab_and_selecting_properties: "Before, when adding a statement, I could type the property ID and then press tab, which would select the property and switch to the text field for the value. Today it seems to no longer work, if I press tab, it tabs elsewhere on the page, and instead I have to press down, enter and then tab for it to work." This for example happens when entering url instead of URL in the property field for a statement. Now the alias url has been added to the property to "fix" this.
The TAB key is not bound to selecting a property as long as no suggestions are offered by the entity selector. So, tabbing to the value input box will only work as soon as suggestions (of which one may be selected) are offered. The bug may refer to (a) a performance issue regarding the API call(s), (b) bug #44746 or (c) a general conceptual issue (Why is the value box visible only after selecting a property?).
I think the bug is fairly simple. It's a "please be case insensitive" request. If you type "URL" you are able to press tab with the expected behavior. If you type "url" you are not. I do have to agree to the reporter. It doesn't make much sense to be case sensitive here, in my opinion. I would love to take and fix this.
