Rightclicking it will also open the mail if OE is still in default.
If you don't want to see what's in the mail turn the preview pane off.
View>Layout>preview pane.
If you think you may want to do this again on a regular basis put a quick access icon on the top toolbar.
View>Layout>Basic>Customise toolbar.. and find the preview icon in the left and add it to the right column.
Close>apply and you should have a preview icon on top which you can use to instantly turn your preview pane off and on.
The answer you are looking for may be that you need more time to view and then, if desired, delete, before the message is automatically �opened�.
If so, on the Outlook Express tool bar click �Tools�, then click �Read�, then, under Reading Messages, put a tick in the box against �Mark message read after displaying for� X �seconds�. Then, in place of X choose however many seconds you need to respond before the message is automatically �opened�. I choose 20 seconds, which I find long enough.