Some of you has express some shortcut delay or not working issues. Recent stability upgrades of Natron has change from previous snapshot releases. Continue reading and you will have an explanation of the changes regarding “Mouse Over Focus” & “Click Focus.”
The "highlighted" pane (in yellowish in the tab name) has temporary "mouse over" focus, and will receive shortcuts from the keyboard. If they are not interpreted then they will be sent to the "click" focus widget (the one in dark orange).
The reason why some people wonder why the "D" shortcut does not work is because they probably either don't have mouse over the node graph, or the node graph does not have click focus.
Some key binds are for example intercepted by 2 widgets, e.g: the "L" key bind in the node graph means "Rearrange nodes", whilst in the viewer is means "Start playback". If the viewer has mouse over focus and the node graph has the click focus, the L shortcut will be sent to the viewer. If on the other hand the viewer does not have mouse over focus, it will be sent to the node graph. If none of them has any kind of focus, the event will not be caught.