A typical workspace setup for me is two zones side by side, with the left-hand zone wider than the right. Frequently when I amplify to a resource or hit command-N for a new search tab, a third zone appears on the right, below the original right-hand zone. If I have the instant details window open (as part of the workspace, along the bottom, not a separate floating palette), and then try to move the newly created tab in the bottom right zone to the top right zone, I will be told that there is not enough space for the tab to be moved. This makes no sense, as there is already a tab of the same size in the zone I'm moving to, and the zone will actually expand vertically because the bottom zone will disappear. If I close Instant details, I can move the tab with no difficulties.
This is happening on my Mac (OS 10.9.2) I can't remember if it also happens on my Windows Vista installation, and I'm not at the church to check on that today, but I will try to do so and report back.