Maxim reported a bug in the filebrowser, where the post forms may not work properly, because they are omitting the query string. This was introduced in r1035 (and released with CMSimple_XH 1.6), because I noticed that the empty values of the action attributes were faulted by the W3C validator for HTML5. Actually the HTML5 CR says:
(emphasis mine)The action and formaction content attributes, if specified, must have a value that is a valid non-empty URL potentially surrounded by spaces.
However, the HTML 4.01 recommendation specifies the action attribute as #REQUIRED.
So I used "#" as value of the action attribute, which is a valid URI according to RFC 2396, albeit an unusual one. Strangely, this requests the current URL with an empty fragment on my local machine, and apparently on many others, but not on all servers--from the same browser.
PS: Fixed by explicitely building the action attribute value (r1320).