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One of my UIs has a problem where it can chug down if you throw too much data at it. The underlying problem is formatting I'm applying to a native LabVIEW multicolumn listbox (MCLB). I'm not aware of any way to get events out of the MCLB when an item is scrolled into view, etc, so the application just blindly applies formatting to the entire list. Not a problem when I wrote the application because the data set was at most bounded to perhaps 1000 rows. Being in R&D, we're never happy though and my colleagues who use the application started throwing data sets at it that can have something like 100 000 rows. Yeah, the UI bogs down for minutes at that point, even with UI updates being deferred etc. Simply performing hundreds of thousands of operations on the MCLB even with no UI updates takes patience. Now ideally I'd like to have better support for the native MCLB, but for now I need to work with what I got so I figured I'd kludge together a pseudo virtual MCLB in native G-code. Here's a proof of principle: virtual mlcb lv10.vi If you run the VI and generate some stupidly large data sets, say 100000x8, you'll see that the render time hopefully stays constant as you scroll through the data, and with a little luck is reasonably fast. Now if I could make a virtual tree view...