Inventory control offers 4 levels of  context dependent "time out"s ( lock out from menumode with player controls disabled ) to add a missing element of gameplay realism and challenge:
 A) Potion, ingredient and enchanted item use time-outs
 B) Equipment change during combat time-outs*
 C) Equipment change during combat disallowed [ only weapons and shields may be changed ]
 D) Equipment change out of combat time outs* and disallowed in combat
              *disallowing changing rings under gloves/gauntlets, shirt under cuirass, cuirass under robe, etc.

Inventory controls levels A)-D) can be cycled through by holding down Shift-I(nventory)-C(ontrol) buttons for >1second to cycle through them:
Level 0: Disables the mod for vanilla behavior
Level 1: A) above
Level 2: A)+B) above  
Level 3: A)+B)+C) above 
Level 4: A)+B)+C)+D) above
The mod will default to Level 3 on first load.

Hold down the SHIFT-I-C key combination for ~1sec to cycle through Level 0-4 settings ("I" and "C" for Inventory Control)

Both menu mode and quick key item use and/or equiping are affected.
Next/Previous ready enchanted items are restricted to equipped items for Level >=2 (so you only cycle through equipped items)

The present release requires default key assignments:
 "1"-"0" = Quick Keys (outside menu mode)
 "-","=" = Next/Previous Ready Item (outside menu mode)
 "[","]" = Next/Previous Weapon (outside menu mode)
 space   = Activate, Pick Up (outside menu mode)
 Left Mouse Button = Pick Up / Drop (menu mode)
 Right Mouse Button = Enter/Exit Menu mode

Requires:
MWSE v0.9.5-alpha.20150829 ( or later ) [ https://github.com/Merzasphor/MWSE ]
Morrowind Code Patch (MCP) v2.2beta (or later ) [ http://www.nexusmods.com/morrowind/mods/26348/? ]
"Incorrect item sound fix" required to detect potion and ingredient consumption
"Enchanted item rebalance" optional; 4s MCP cool down will be in parallel with time outs

See the video for a short demonstration

V1.01 fixes a bug reported by Lucas9 when trading equipped items by disabling inventory control when targeting a friendly trader or followe
v1.02 - changes the inventory control token name to 'nothing'.  Thanks to harrytom for suggesting it.
v1.10 - utilizes MWSE2.0 xContentListFiltered for improved efficiency (reduced lag on inventory/container openings/closings with large item counts)