CPU impact of hovering over grid records

[hin3x]

Hello,

Recently we noticed (while performance testing our app) that there is quite an impact on the CPU when we move the mouse over list-grid records (from top to bottom and back). The faster the mouse moves the higher the CPU use stats go.

I expected some issue in our app with the application of styling but I was surprised that this was noticeable in the showcase too.

When you have a look at the 'Cell Styles' sample (http://www.smartclient.com/smartgwt/...ce_cell_styles) you can see that the CPU usage goes berserk (40% on a single CPU) when hovering the rows fast.

I have tested this on Windows XP with IE8, FF11 and Chrome 18. All show similar behavior.

We are on SC_SNAPSHOT-2012-02-01_v8.3d/Pro Deployment (built 2012-02-01), but since it is noticeable in the showcase too I assume the version information is not that important for this particular case.

Is something wrong here or is this 'expected' behavior due to the inability of the current browsers?

thanks

[Isomorphic]

Depending on the skin (some use an image gradient for rollover), yes this is normal.

[hin3x]

It is the 'Enterprise Gray' skin which defaults on the showcase, in the example I can notice it on both grids.

[Isomorphic]

Yes, that is one where a gradient is used. Re-rendering a gradient based on a .png as the mouse moves around is expected to cause some CPU usage but no visual lag - this is what we see on test machines.