Update with workable prototype.

Penumbra/UI/ModsTab/Groups/CombiningModGroupEditDrawer.cs

@@ -1,4 +1,10 @@
+using Dalamud.Interface;
+using ImGuiNET;
+using OtterGui;
+using OtterGui.Raii;
+using OtterGui.Text;
 using Penumbra.Mods.Groups;
+using Penumbra.Mods.SubMods;
 
 namespace Penumbra.UI.ModsTab.Groups;
 
@@ -6,6 +12,100 @@ public readonly struct CombiningModGroupEditDrawer(ModGroupEditDrawer editor, Co
 {
     public void Draw()
     {
-        
+        foreach (var (option, optionIdx) in group.OptionData.WithIndex())
+        {
+            using var id = ImUtf8.PushId(optionIdx);
+            editor.DrawOptionPosition(group, option, optionIdx);
+
+            ImUtf8.SameLineInner();
+            editor.DrawOptionDefaultMultiBehaviour(group, option, optionIdx);
+
+            ImUtf8.SameLineInner();
+            editor.DrawOptionName(option);
+
+            ImUtf8.SameLineInner();
+            editor.DrawOptionDescription(option);
+
+            ImUtf8.SameLineInner();
+            editor.DrawOptionDelete(option);
+        }
+
+        DrawNewOption();
+        DrawContainerNames();
+    }
+
+    private void DrawNewOption()
+    {
+        var count = group.OptionData.Count;
+        if (count >= IModGroup.MaxCombiningOptions)
+            return;
+
+        var name = editor.DrawNewOptionBase(group, count);
+
+        var validName = name.Length > 0;
+        if (ImUtf8.IconButton(FontAwesomeIcon.Plus, validName
+                ? "Add a new option to this group."u8
+                : "Please enter a name for the new option."u8, default, !validName))
+        {
+            editor.ModManager.OptionEditor.CombiningEditor.AddOption(group, name);
+            editor.NewOptionName = null;
+        }
+    }
+
+    private unsafe void DrawContainerNames()
+    {
+        if (ImUtf8.ButtonEx("Edit Container Names"u8,
+                "Add optional names to separate data containers of the combining group.\nThose are just for easier identification while editing the mod, and are not generally displayed to the user."u8,
+                new Vector2(400 * ImUtf8.GlobalScale, 0)))
+            ImUtf8.OpenPopup("DataContainerNames"u8);
+
+        var sizeX = group.OptionData.Count * (ImGui.GetStyle().ItemInnerSpacing.X + ImGui.GetFrameHeight()) + 300 * ImUtf8.GlobalScale;
+        ImGui.SetNextWindowSize(new Vector2(sizeX, ImGui.GetFrameHeightWithSpacing() * Math.Min(16, group.Data.Count) + 200 * ImUtf8.GlobalScale));
+        using var popup = ImUtf8.Popup("DataContainerNames"u8);
+        if (!popup)
+            return;
+
+        foreach (var option in group.OptionData)
+        {
+            ImUtf8.RotatedText(option.Name, true);
+            ImUtf8.SameLineInner();
+        }
+
+        ImGui.NewLine();
+        ImGui.Separator();
+        using var child = ImUtf8.Child("##Child"u8, ImGui.GetContentRegionAvail());
+        ImGuiClip.ClippedDraw(group.Data, DrawRow, ImGui.GetFrameHeightWithSpacing());
+    }
+
+    private void DrawRow(CombinedDataContainer container, int index)
+    {
+        using var id = ImUtf8.PushId(index);
+        using (ImRaii.Disabled())
+        {
+            for (var i = 0; i < group.OptionData.Count; ++i)
+            {
+                id.Push(i);
+                var check = (index & (1 << i)) != 0;
+                ImUtf8.Checkbox(""u8, ref check);
+                ImUtf8.SameLineInner();
+                id.Pop();
+            }
+        }
+
+        var name = editor.CombiningDisplayIndex == index ? editor.CombiningDisplayName ?? container.Name : container.Name;
+        if (ImUtf8.InputText("##Nothing"u8, ref name, "Optional Display Name..."u8))
+        {
+            editor.CombiningDisplayIndex = index;
+            editor.CombiningDisplayName  = name;
+        }
+
+        if (ImGui.IsItemDeactivatedAfterEdit())
+            editor.ModManager.OptionEditor.CombiningEditor.SetDisplayName(container, name);
+
+        if (ImGui.IsItemDeactivated())
+        {
+            editor.CombiningDisplayIndex = -1;
+            editor.CombiningDisplayName  = null;
+        }
     }
 }

Penumbra/UI/ModsTab/Groups/ModGroupEditDrawer.cs

@@ -58,6 +58,9 @@ public sealed class ModGroupEditDrawer(
     private IModOption? _dragDropOption;
     private bool        _draggingAcross;
 
+    internal string? CombiningDisplayName;
+    internal int     CombiningDisplayIndex;
+
     public void Draw(Mod mod)
     {
         PrepareStyle();
@@ -275,6 +278,7 @@ public sealed class ModGroupEditDrawer(
     [MethodImpl(MethodImplOptions.AggressiveInlining)]
     internal string DrawNewOptionBase(IModGroup group, int count)
     {
+        ImGui.AlignTextToFramePadding();
         ImUtf8.Selectable($"Option #{count + 1}", false, size: OptionIdxSelectable);
         Target(group, count);