Clicking the down caret to the right of the current display size (Fixed size) brings up the sizing options. There are three sizing options, as seen in the following screenshot:

The following is a short description of the sizing options:

• Fixed size: This is the default size. A fixed size means that the dashboard stays the same size regardless of how big the screen of the viewer is. If the dashboard extends across or below the size of the screen then the user will be presented with scroll bars. There are pros and cons to each sizing option. With fixed-size dashboards, you can control the exact position of objects. If you choose to use floating elements, a fixed-size dashboard is the suggested option. When using a fixed-size dashboard, you can select from the following suggestions for specific devices:

• Automatic: Select this option if you want Tableau to determine display settings. Tableau will attempt to resize the window based on the user's screen size. 

• Range: With the Range setting, you select a minimum and maximum display size. The dashboard resizes to the minimum display if the user's display is smaller than the minimum selected. Similarly, the dashboard resizes to the maximum display if the user's display is larger than the maximum selected.