Hi Michal Straka,
Thank you for your interest in Syncfusion Products.
Yes, this can be achieved using the Window control. The Essential Tools Window control is a fully customizable control with dialog like functionality.It can be dislayed in modal dialog or non modal dialog mode.I have created a sample using Window Control and please refer the below link,
http://websamples.syncfusion.com/samples/Tools.Web/6.3.0.32/F75927/main.htmAlso please refer the below link for online samples which illustrates the idea of Window control,
http://www2.syncfusion.com/infrastructure/web/tools.web/samples/2.0/NotificationPackage/Window/WindowDialogBoxes/CS/WindowDialogBox.aspxPlease let me know if you have any concerns.
Thanks,
Rekha