I tried to merge four topics today. I got the following error. After clicking on "back" ("Zurück") I got a session timeout message, but I was still logged in.
Merging two topics makes no problems.
It says you can only do two topics at a time and you do more than that, so I will not consider this as a bug but more on feature upgrade. Basically you want to be able to merge more topics than the default.
Current solution will be to do it two topics on each merge, until you merge them all. I count that as three times.
It does? Where? Oh, you mean the error message itself? If that's the limit, then it is not a bug, you are right. There should be a note about that somewhere.
head scratch .... I think It should allow you to merge more than one at a time.
So we may need to update that line of text so its actually correct :P
Although the bug is showing up in merge topics, I think its a bit more general of an issue, albeit very rare in the code. ElkArte uses a centralized post and validation class to interact and validate form data. I'd start with this edit to the HttpReq.class.php in sources and see how that goes.
// To the validator
$this->_dataValidator->validation_rules(array());
$this->_dataValidator->sanitation_rules(array($name => $sanitize));
$this->_dataValidator->validate($this->_param);
// To the validator
$this->_dataValidator->validation_rules(array());
$this->_dataValidator->sanitation_rules(array($name => $sanitize));
if (is_array($this->_param[$name]))
$this->_dataValidator->input_processing(array($name => 'array'));
$this->_dataValidator->validate($this->_param);
That scripturl issue in the image looks to be your theme issue, I don't see that in the default theme (your probably missing a global $scripturl; in your theme function.
Not being able to press back is "normal" as you submitted a form, going back is not going to work since your are effectively trying to submit again. The message could be better, but the result would be the same, denied !
I'll track this for 1.1.5 ETA: https://github.com/elkarte/Elkarte/issues/3216