Management summary: Ctrl + Shift + S overrules all conditional show expressions making every hidden sheet and sheet object visible.
Full story: Condtional show expressions are used in QlikView to show or hide a sheet or sheet object depending on if a predefined condition has been met. While this is extremely useful functionality to make your applications more user-friendly, it can be a real hassle during development.
If you want to edit a sheet or object when its show condition has not been met, you either have to make a selection that matches the condition, or you have to dig deep into the menu (Settings | Document Properties | Security | Show All Sheets and Objects) to disable, and when you’re done re-enable, conditional display. We all have better things to do with our time, for example reading blog posts that are way longer than they need to be.
Fortunately, in QlikView Desktop (‘classic’ view, not WebView) there is a shortcut: Ctrl + Shift + Soverrules all conditional show expressions making every hidden sheet and sheet object visible. Now you know.