* the newly expanded columns should line up on top.
* the elements should not be pushed lower when a taller child element is introduced. This hides the elements on the left column(s).
* to keep a visual track of how I arrived at the current level, set background of the clicked elements to a different colour. This should provide the same functionality provided by point 1 above, without taking away the visual cue.
In summary, please take a look at how Apple Finder implements directory browsing using vertical columns.
* the elements should not be pushed lower when a taller child element is introduced. This hides the elements on the left column(s).
* to keep a visual track of how I arrived at the current level, set background of the clicked elements to a different colour. This should provide the same functionality provided by point 1 above, without taking away the visual cue.
In summary, please take a look at how Apple Finder implements directory browsing using vertical columns.