Preview 
The following options are available from the drop down menu:
· ‘Preview
current’ 
shows the
original drawing as it will appear when imported in the project.
· ‘Load and
preview current’ is similar
to ‘Preview current’, but also applies any changes in the properties made by the
user while importing the file (e.g. resolution).
· ‘Preview
using PDF reader ’ 
opens a
pdf file in the default Pdf Reader application of your PC.