ClickableWhenViewportHIdden determines whether a PluginToolbarButton may be clicked while the game viewport is hidden, such as when a Script is being edited in another tab. In the image below, various plugin toolbar buttons are visible. Some are enabled as a result of this property being true, such as the Localization Tools button.

Typically, this property is good to enable if an action triggered by a plugin button’s PluginToolbarButton/Click|Click event doesn’t occur in the game world (Workspace). For example, a button that opens a widget should have this property be true, as showing a widget is visible to the user even if the game view isn’t visible.