Combine parallel dimension lines

You can manually combine a group of two or more parallel dimension lines into one line.

Hold down Ctrl and click the dimension lines you want to combine.
On the Dimensioning tab, click Combine lines.

You can also right-click and select Combine dimension lines.

Note that you cannot uncombine the combined dimension lines using a single command, there is no command for that. To return to the state where the dimensions were not combined, you need to create the dimensions again from the start. However, there is a workaround: You can activate the Select drawing single dimensions selection switch, click a single dimension in the combined dimensions, and then drag the selected dimension to the desired location.