[INTERNAL][FIX] P13nColumnsPanel : bug fix and unit test extension

Change-Id: Ib6d752c13d1c93439cbc41a555182d2e036419ff
[INTERNAL] m.Slider: minor formatting improvements

Change-Id: I76a033c27fe1b43a9b687783f7460aabf4cd3ee4
Merge "[INTERNAL][FIX] P13nColumnsPanel : bug fix and unit test extension"