From Xojo Documentation
Sets the paragraph alignment for entire contents of the control.
Use the TextAlignments enumeration to get/set the value of this property.
For the TextArea control, use the SelectionAlignment property to set paragraph alignments for individual paragraphs. Currently the Default alignment is the same as Left aligned. Setting the alignment on Linux requires GTK+ 2.4 or greater.
This example is in the Initialized event of the control.