Projects tree depicts the projects hosted inside for current session. It also provides the interface to Create, Load, Build and various other actions associated with projects and the source files comprising those projects.
Projects tree is a left-side docking widget and has an attribute to hide or show, resize, etc. This setting is remembered for subsequent run. It exposes standard navigational behavior, viz., left-click: selects node, right-click: context-menu, double-click: activates next action depending upon the node type.