Hello,
sorry but this fix doesnt work for me!
For the moment in my site, I had removed the css property
filter: Alpha(Opacity = 30) /*{opacityOverlay}*/;
Now, I get your fix and re-add the css property and I try but the memory increase each time I display a dialog in IE :(
With the first fix (an array with oldInstances), the memory increase just one time but js error after 3 dialogs open :(
In IE, the memory increase differently, its related to the height of the page, so if you have a huge page -> IE use a lot of memory!!!