I am a longtime Lightroom user, now with 4.3. I import my files from my D800e with a card reader as dng's. Occasionally, when I click on an image in the grid view, the histogram does not show, regardless of how long I wait. If I bring it into loupe view, it also does not show. If I put it into develop mode, the histogram is always there. This seems to happen randomly. I find this frustrating behavior. Has anyone else experienced this? It has persisted through a number of upgrades. I guess I should ask Adobe but value the resource here. Thanks for any help.