I installed version 4.2.8 (265) on new MacBook
I can see Workspace history and checkout just fine but with changes made, in File Status tab of Workspace it shows as 72 new files in list in rectangle on Commit button; however, I only can see the left sidebar on the left and the diff window (with commit window on very bottom) on the right; that is, there is no column for staged and unstaged file windows as it has on other installs). This is despite setting pending, alphabetically, flat list and split view staging. When I hover over the line between the sidebar it only allows the sidebar and the difference/commit window to resize horizontally.