Reveal Hidden Elements - Revit

Question
How can you check which model / annotative elements/categories have been hidden in Revit?

Answer
Click the Reveal Hidden Elements button on the View Control Bar at the bottom of your view window. If you’re not sure which is the correct button, just hover over each button on the View control Bar.? Hidden elements will outline in red. Select the elements that you want to unhide right click and select unhide in view elements/categories. Lastly click the Reveal Hidden Elements again and the hidden objects will reappear.