Hi, 

I think this is a problem with your code.

I ran your sample and I see the issue you describe. But it's actually much easier to reproduce than you have here. You don't need the isl file at all. I was able to reduce the issue down to two lines of code:

this.Icon = Icon.ExtractAssociatedIcon(System.Windows.Forms.Application.StartupPath + @"\AppIconDefaultON.ico");
this.ultraFormManager1.FormStyleSettings.FormDisplayStyle = Infragistics.Win.UltraWinToolbars.FormDisplayStyle.RoundedSizable;

If you do not set the icon at run-time, the problem goes away. Which means that the default icon works fine and it's only your icon assigned at run-time that has an issue.

So I tried creating a new icon and assigning it at run time and I got the same problem. So that rules out the icon itself as the issue.

So either there is some inherent problem with setting the form's icon at run-time or else it's the way in which you are setting it that's causing a problem.

So I tried loading the icon in a different way:

//this.Icon = Icon.ExtractAssociatedIcon(System.Windows.Forms.Application.StartupPath + @"\AppIconDefaultON.ico");
this.Icon = new Icon(System.Windows.Forms.Application.StartupPath + @"\AppIconDefaultON.ico");
this.ultraFormManager1.FormStyleSettings.FormDisplayStyle = Infragistics.Win.UltraWinToolbars.FormDisplayStyle.RoundedSizable;

And this works fine. So the issue must be in the ExtractAssociatedIcon method. That method must be modifying or corrupting the icon in some way.

I was able to reproduce it in a sample. Attaching

Also I was not able to reproduce the same behaviour in the sample I tried to build

I am using UltraFormManger in the specific form. The infragistics version is 12.1.20121.2038.