How do I tell the dimensions of the current selection in GIMP?

In GIMP, the status bar at the bottom of the window will show you the dimensions while you are selecting, but it disappears when you finalize the selection. I suspect that is because the selection can be shapes other than rectangle. If you want to see it afterwards, make sure the Windows --> Dockable Dialogs --> Tool Options pane is enabled. It may already be docked on your Toolbox. This will show you the position and size of a Rectangle Select. You can also modify the size of the selection from this pane.

I am using GIMP 2.8 on Windows.

If the above solutions are inelegible and your selection equals the current layer, you might also measure the size of the layer using "Layer" -> "Scale Layer".

Anyone knows how to measure selected area? I have irregular shape selected, and I want to know what is the area of that selection, for example in square pixels.

Edit:

I found the answer by myself, simplest solution was to open histogram dialog (Windows → Dockable Dialogs → Histogram), there you can find pixels count of selected area.