Hi, I found out that using something like addStylename() in an onmouseover can have really catastrophic effects on performance in IE (6/7 and 8). In fact IE8 seems to be worse than the older versions. In my applications the browser locks up for many seconds even minutes running at 100% CPU. DynaTrace reveals that the browser is busy doing layout calculations.
For example we were doing a style change when moving the mouse over a big table. In some situations this would block the browser for many seconds (sometimes minutes, depending on the complexity of the UI). If I just directly set the style attribute changes directly in the code it takes almost no CPU with the same complex UI. The problem here is that I loose a lot of flexibility in my UI to use CSS to do the styling (what if I want to change more than just the color for example). I know there is something like CssResource, but as I understand it, it will not solve the issue in this case since I still need to use an addStyleName. Would there be a way, or wouldn't it be an great Idea, that GWT would have support in CssResource to copy style attributes from the CssResouce directly in the styles of the element that I am targetting ? That way I would not need a addStylename/addClassname but I still have the flexibility to write down these changes in a CSS file. Or did I overlook such a feature ? As I understood, the declarative UI mechanism in GWT is doing such things, but in our apps we can not use this. Best regards, David Nouls -- http://groups.google.com/group/Google-Web-Toolkit-Contributors
