I'm experimenting with creating some shields, which have a new base file. The new shields work fine and I can spawn them in the editor game, but any new shield using a different base file than vanilla will not be displayed in the Item Editor list. If I change it back to use the standard base file it appears in the list again.

My base file, located in: media\units\items\shields\
[UNIT]
<STRING>CREATEAS:EQUIPMENT
<STRING>UNITTYPE:NORMAL SHIELD
<INTEGER>ARMORMIN:40
<INTEGER>ARMORMAX:40
<INTEGER>VALUE:75
<BOOL>DONTCREATE:true
<STRING>FALL_SOUND:Item Fall
<STRING>TAKE_SOUND:MetalGet
<STRING>LAND_SOUND:MetalDrop
<INTEGER>BLOCK_CHANCE:7
<STRING>GAMBLER_ICON:icons__shield01
<INTEGER>RARITY_AMR_MOD:100
<INTEGER>DEFENSE_REQUIRED:45
<INTEGER>DEXTERITY_REQUIRED:0
<INTEGER>MAGIC_REQUIRED:0
<INTEGER>STRENGTH_REQUIRED:30
<STRING>NAME:tla_base_shield
<STRING>UNIT_GUID:-2030796240000217279
[EFFECT]
<STRING>NAME:40
<STRING>ACTIVATION:PASSIVE
<STRING>TYPE:PERCENT KNOCK BACK RESISTANCE
<BOOL>NONMAGICAL:true
<FLOAT>RESISTANCE:40
[/EFFECT]
[/UNIT]

My new shield, also located in: media\units\items\shields\
[UNIT]
<STRING>BASEFILE:media\units\items\shields\tla_base_shield.dat
<INTEGER>DAMAGE_PHYSICAL:0
<TRANSLATE>DISPLAYNAME:Spellblade Shield
<STRING>ICON:icon_weapon_shield07
<INTEGER>LEVEL:23
<STRING>MESHFILE:shield07
<STRING>NAME:tla_spellblade_shield_start
<INTEGER>RARITY:100
<STRING>RESOURCEDIRECTORY:media/models/weapons/_Shields
<INTEGER>STRENGTH_REQUIRED:45
<INTEGER>DEFENSE_REQUIRED:45
<INTEGER>SOCKETS:2
<INTEGER>MAX_SOCKETS:2
<STRING>UNIT_GUID:-2458686679345536827
<INTEGER>ARMOR_PHYSICAL:100
[/UNIT]

Everything seems to be in order, as far as I can tell, and like I said. The shield can be spawned and used in the editor.

Has anyone else noticed any similar issues to this?

OK, thank you, RnF. A very annoying bug...