private bool GUIMask(string label, string tooltip, string maskKeyword, string channelKeyword, string feature = null, bool enabled = true, bool increaseIndentLevel = false, bool visible = true, string helpTopic = null)
    {
        string[] labelsAndKeywords = new string[] {
            "Off|",
            "Main Texture|mainTex",
            "Mask 1|mask1", "Mask 2|mask2", "Mask 3|mask3"
        };

        if (!enabled)
        {
            GUI.enabled = false;
        }
        if (increaseIndentLevel)
        {
            label = "▪  " + label;
        }

        string[] labels = new string[labelsAndKeywords.Length];
        string[] masks  = new string[labelsAndKeywords.Length];
        string[] uvs    = new string[] { "Main Tex UV", "Independent UV" };

        for (int i = 0; i < labelsAndKeywords.Length; i++)
        {
            string[] data = labelsAndKeywords[i].Split('|');
            labels[i] = data[0];
            masks[i]  = data[1];
        }

        int curMask = System.Array.IndexOf(masks, TCP2_ShaderGeneratorUtils.GetKeyword(mCurrentConfig, maskKeyword));

        if (curMask < 0)
        {
            curMask = 0;
        }
        TCP2_Utils.TextureChannel curChannel = TCP2_Utils.FromShader(TCP2_ShaderGeneratorUtils.GetKeyword(mCurrentConfig, channelKeyword));
        if (curMask <= 1)
        {
            curChannel = TCP2_Utils.TextureChannel.Alpha;
        }
        string uvKey = (curMask > 1) ? "UV_" + masks[curMask] : null;
        int    curUv = System.Array.IndexOf(uvs, TCP2_ShaderGeneratorUtils.GetKeyword(mCurrentConfig, uvKey));

        if (curUv < 0)
        {
            curUv = 0;
        }

        if (mHideDisabled)
        {
            visible = enabled;
        }

        if (visible)
        {
            EditorGUILayout.BeginHorizontal();
            float w = 166;
            if (!string.IsNullOrEmpty(helpTopic))
            {
                w -= 20;
                TCP2_GUI.HelpButton(label.TrimStart('▪', ' '), helpTopic);
            }
            TCP2_GUI.SubHeader(label, tooltip, (curMask > 0) && enabled, w);
            curMask     = EditorGUILayout.Popup(curMask, labels);
            GUI.enabled = curMask > 1;
            curChannel  = (TCP2_Utils.TextureChannel)EditorGUILayout.EnumPopup(curChannel);
            curUv       = EditorGUILayout.Popup(curUv, uvs);
            GUI.enabled = mGUIEnabled;
            TCP2_GUI.HelpButton("Masks");
            EditorGUILayout.EndHorizontal();
        }

        TCP2_ShaderGeneratorUtils.SetKeyword(mCurrentConfig.Keywords, maskKeyword, masks[curMask]);
        if (curMask > 0)
        {
            TCP2_ShaderGeneratorUtils.SetKeyword(mCurrentConfig.Keywords, channelKeyword, curChannel.ToShader());
        }
        if (curMask > 1 && !string.IsNullOrEmpty(uvKey))
        {
            TCP2_ShaderGeneratorUtils.SetKeyword(mCurrentConfig.Keywords, uvKey, uvs[curUv]);
        }
        TCP2_ShaderGeneratorUtils.ToggleSingleFeature(mCurrentConfig.Features, feature, (curMask > 0));

        if (!enabled)
        {
            GUI.enabled = mGUIEnabled;
        }

        return(curMask > 0);
    }