I have implemented common solution for error dialog handling but unfortunatelly for me each html file that wants to show error dialog now needs to link two additional style files: dhtmlxwindows.css and skins/dhtmlxwindows_dhx_skyblue.css
This is too complicated as there are many files and link part of html files grow bigger and bigger and things are being less simple and readable.
I tried to change file dhtmlx.css to include those two additional css files automatically but I failed when I put it to end or start. It looks like there is mess in final style or style is lost. Buttons are hidden, position of text is moved and it is somehow transparent.