Reassigned.

@ftack: the line and filling toolbar has a shadow button. Clicking on it applies
a shadow to all selected objects. Does that button do what you want?

all: There is no straightforward method to apply a custom shadow effect to 2 or
more line objects simultaneously. 

I used OOo-dev 3.3.0 DEV300m75 on Mac in my investigations. 

I found 3 places where shadow effects can be applied to line objects:

* The shadow button on the line and filling toolbar
* Format->Line... ("Shadow" tab)
* Format->Area... ("Shadow" tab)

The toolbar button works, but I could only use it to apply the default shadow
effect.

A stated in the original report, the shadow tab is only available on the
Format->Line... dialog when 1 line object is selected. If 2 or more objects are
selected, the tab is not present.

The only remaining place I found to apply a custom shadow effect is the shadow
tab on the Format->Area... dialog. But:

!!!
This dialog is grayed out in the Format menu if only line objects are selected.
!!!

In my testing, I discovered a workaround. If another type of object is selected
along with the lines, then this menu option is available.

So to create a custom shadow effect on multiple lines, I need to

* create a rectangle
* select the lines and the rectangle
* use Format->Area...Shadow
* delete the rectangle

This seems a bit awkward and confusing.

On a side note: In Writer, Format->Object->Area...Shadow behavior is different
than Impress. The menu item is always available, so you *can* use it to apply a
shadow to multiple lines. Format->Object->Line...Shadow behaves the same way as
it does in Impress.

I think this issue can be confirmed by now.