Guto You may want to uncheck Hide viewport skin bones in the tree view settings:
When checked, bones that are in a skin and are not active because their skin is not visible are not shown in the viewport. Also, their bone rows are not shown in the dopesheet or graph.
When unchecked, all bones are made active, regardless of which skins are visible. If you press Ctrl+A in this state, you can select all bones included in the inactive skin.
It can be helpful to see all the bones, but can also be misleading for skin bones to be active when their skin is not visible. Bone warnings that will not render correctly at runtime may render correctly when this setting is unchecked. For that reason, this setting is checked by default and should be checked most of the time.
