I'm not sure public is the right accessibility yet. Usually, we would make this protected, so that a mod providing a window override can use a custom value.
Public could be right if there was a way for mods to register to an event that would let it change the value after Setup() (so that its value wins over the default) but before ShowLocationPicker (so it actually gets used). This way, mods could customize this behavior without overriding the window. I haven't looked if we have any such event

I'm not sure I like the explicit check for SDF vs non-SDF. Is that what we do for books and other auto-formatted text boxes? I know quest text is manually formatted to support non-SDF, but I think books are handled in code

I'm not sure public is the right accessibility yet. Usually, we would make this protected, so that a mod providing a window override can use a custom value. Public could be right if there was a way for mods to register to an event that would let it change the value after Setup() (so that its value wins over the default) but before ShowLocationPicker (so it actually gets used). This way, mods could customize this behavior without overriding the window. I haven't looked if we have any such event

Okay, if simplest/most convenient way is subclassing, making it a protected virtual property

I tried

diff --git a/Assets/Scripts/Game/UserInterfaceWindows/DaggerfallListPickerWindow.cs b/Assets/Scripts/Game/UserInterfaceWindows/DaggerfallListPickerWindow.cs
index 714a084dc..05b46792a 100644
--- a/Assets/Scripts/Game/UserInterfaceWindows/DaggerfallListPickerWindow.cs
    b/Assets/Scripts/Game/UserInterfaceWindows/DaggerfallListPickerWindow.cs
@@ -81,6  81,8 @@ namespace DaggerfallWorkshop.Game.UserInterfaceWindows
             // Create list box
             listBox.Position = new Vector2(26, 27);
             listBox.Size = new Vector2(138, 72);
             listBox.RectRestrictedRenderArea = new Rect(listBox.Position, listBox.Size);
             listBox.RestrictedRenderAreaCoordinateType = BaseScreenComponent.RestrictedRenderArea_CoordinateType.ParentCoordinates;
             listBox.OnUseSelectedItem  = ListBox_OnUseSelectedItem;
             pickerPanel.Components.Add(listBox);
 
diff --git a/Assets/Scripts/Game/UserInterfaceWindows/DaggerfallTravelMapWindow.cs b/Assets/Scripts/Game/UserInterfaceWindows/DaggerfallTravelMapWindow.cs
index 4e4cf5d79..77d61d045 100644
--- a/Assets/Scripts/Game/UserInterfaceWindows/DaggerfallTravelMapWindow.cs
    b/Assets/Scripts/Game/UserInterfaceWindows/DaggerfallTravelMapWindow.cs
@@ -1565,7  1565,6 @@ namespace DaggerfallWorkshop.Game.UserInterfaceWindows
         {
             DaggerfallListPickerWindow locationPicker = new DaggerfallListPickerWindow(uiManager, this);
             locationPicker.OnItemPicked  = HandleLocationPickEvent;
-            locationPicker.ListBox.MaxCharacters = LocationPickerMaxCharacters;
 
             for (int i = 0; i < locations.Length; i  )
             {

but somehow it didn't work (text not clipped inside the ListBox. I'm not sure what I'm missing

Also, the same issue happens with the list of spells (spell merchant, spellbook)

but somehow it didn't work (text not clipped inside the ListBox. I'm not sure what I'm missing

My current hypothesis is that ShowLocationPicker is calling AddItem() of the ListBox before its parent DaggerfallListPickerWindow has been SetUp(), which is a problem because it's AddItem() that propagates the RestrictedArea of the ListBox to its elements

My analysis was correct, and simplest fix I could think of was to subclass DaggerfallListPickerWindow to delay calls to listBox.AddItem(s) to the end of Setup()
I end up fixing locations list, spell mechant/spell book lists, bookshelves list

Could be factorized further if we decide DaggerfallListPickerWindow should always use restricted area, or would benefit from a constructor with a List to initialize its content; I just tried to keep changes as local as possible.