When running the Sobel edge detect on an image without a selection, the topmost scanline of the output is random garbage. From a very quick glance at the source it seems that the previous row array isn't initialised, so the first row is compared to an array filled with random bytes, causing random output on the first row. I'm not sure about how Sobel is supposed to work anyway, so if this is correct behaviour please excuse my ignorance. I tried to search BugZilla but it didn't bring up anything with "sobel" in it (could be me though, I can't remember any BugZilla ever returning a bug report on any of my queries), so I'm sending it here. If it's being worked on or already fixed please consider this email not sent. Lourens