Thank you for your additional information. In my case I have 3 buttons in my dialog. Accessing only the first button by "k-primary" would not help. The only solution is what you say: "If you need to disable/enable specific button in the Dialog, you could use a selector that is unique for this button."
The problem here is, that KendoUI does not set a unique ID here (neither in some other widgets as I already experienced. See attached screenshot showing how initialised Dialog buttons are defined.
So the one and only possibility to access them specific you need to find the (unique) text of the button:
Well, this is not so nice but it works. Furthermore I need specific button access because I different dialog widgets.
For completeness in case someone else runs into the same problem: My buttons are stretched and I want to reuse the same dialog widget in that case. I use sometimes 3 sometimes 2 buttons. In case of 2 buttons I want to not only disable but hide the button. That works like this in JQuery:
Since all stretched buttons have a "%" width you need to adjust the with of the still displayed buttons:
// 50% in case of 2 displayed buttons
That works fine so far and I tend to use this mechanism.
Thank you Neli (nice name btw. ;)). Your samples helped me to find a well fitting solution!