Mike, The problem is partially solved.
> Can you post a link to this page? No, I can't - since it is a project all the time being developed on localhost. > Is inner-holder-error the outer > most element used for blocking? For example, does your block call > look like this: > > $.blockUI({ > message: $('#inner-holder-error') > > }); Yes - that was the problem. I ported blockui in place of jquery ui dialog box and messed up with div's names. After corection problem of hiding/unhiding divs is solved. > The default settings are meant to handle a simple, short message. But But I still can understand why blockui does not centers my message vertically (horizontally is fine) if I use default options (no css no option changing except message text)? By default centerX and centerY are set to true, right? Here you can see effect: http://trejderowski.pl/trash/blockui.jpg > you can control the position of the message usingblockUI's'css' > option. There is an example on the demos page that shows how to > control position with tall content. Yes. Bus AFAIK all examples, including the one I used: $.blockUI ({ message: $('#inner-holder-error'), css: { top: ($(window).height() - 500) /2 + 'px', left: ($(window).width() - 500) /2 + 'px', width: '500px', height: '500px' } }); requires providing widht and height. And what is most convinient and most welcomed in default settings is that message is being centered vertically and horizontally without providing it's dimensions. At least that what should happen and happens in most situation as for one most important for me effect you can see above - message is not being centered vertically. Cheers, Tomasz