Horizontally centres the selected objects. If only one object is selected in Draw or Impress, the centre of the object is aligned to the horizontal centre of the page.
On Align bar (Collabora Office Impress, Collabora Office Draw), click
Centred
The vertical position of the selected objects is not affected by this command.
To align the individual objects in a group, choose Format - Group - Enter Group to enter the group, select the objects, right-click, and then choose an alignment option.
To align the individual objects in a group, double-click to enter the group, select the objects, right-click, and then choose an alignment option.