Have you been in the situation where you tried to tab through a form, and validation messages that just appeared on the previous field are now taken away? The same happens when clicking in a different field from the one that has a validation message: the click results in the validation messages being removed, and usually a jump in layout as well.
I'd like to have more control, please ;-) by being able to make validation messages disappear on cue. How about a Nanoflow activity?
Please vote if you agree.
That and while we are at it: more focus of Mendix to prettify the UI.