Selecting all files in Finder with column view /folder1/folder2/file1
                /file2
        /folder3
                /file3
        /folder4
                /file4
                /file5
                /file6


Given a folder structure such as this one. When I've got folder2 selected and press Cmd + A or Select All the expected behaviour is that all the files within folder2 will be selected, namely file1 and file2. This happens most of the time, but sometimes when folder2 is selected instead of selecting all the files and folders below folder2, all the files and folders of the same level are selected, namely folder2, folder3 and folder4. 

Does anyone know what causes this? I run Finder with XtraFinder on Mac OS X 10.8.4.
It depends on the way the folder (or other folder-like item) is selected. If you select an item by clicking on it, command-A selects all items in the next column. If you select an item with the keyboard (or by for example revealing a folder in Finder from another application), command-A selects all items in the same column.

You can select all items in the current column by pressing the up or down arrow key and then command-A, or all items in the next column by pressing the right arrow key and then command-A.