Embodiments of a system for automatically managing panes in relation to the application canvas in a user interface. The system includes a pane manager that works in conjunction with applications to provide access to panes while keeping a minimum amount of user content visible. The system allows an application to define a protected canvas size. When a pane is needed, the system determines if sufficient room for the pane exists or can be created by dismissing another pane. If so, the pane is added. If not, the pane may be displayed in a temporary manner. The system also responds to changes in the user interface size. If the user interface size decreases to a point where sufficient room for existing panes is no longer available, one or more of the existing panes are dismissed.