Condition Builder - A dynamic matrix doesn't appear in a list of available questions

[JaneSjs]

T20733 - Dynamic matrix question is not showing while adding logic conditions to other questions
https://surveyjs.answerdesk.io/internal/ticket/details/T20733

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A matrix can be used in exressions: for instance, to check whether a matrix is not empty.

{matrix} notempty

Consider a demo survey JSON:

{
  "logoPosition": "right",
  "pages": [
    {
      "name": "page1",
      "elements": [
        {
          "type": "matrixdynamic",
          "name": "question1",
          "columns": [
            {
              "name": "Column 1"
            },
            {
              "name": "Column 2"
            },
            {
              "name": "Column 3"
            }
          ],
          "choices": [
            1,
            2,
            3,
            4,
            5
          ]
        }
      ]
    },
    {
      "name": "page2",
      "elements": [
        {
          "type": "radiogroup",
          "name": "question2",
          "choices": [
            {
              "value": "Item 1",
              "text": "Yes"
            },
            {
              "value": "Item 2",
              "text": "No"
            }
          ]
        },
        {
          "type": "matrixdynamic",
          "name": "question3",
          "columns": [
            {
              "name": "Column 1"
            },
            {
              "name": "Column 2"
            },
            {
              "name": "Column 3"
            }
          ],
          "choices": [
            1,
            2,
            3,
            4,
            5
          ]
        }
      ]
    }
  ],
  "triggers": [
    {
      "type": "copyvalue",
      "expression": "{question2} = 'Item 1' and {question1} notempty",
      "fromName": "question1",
      "setToName": "question3"
    }
  ]
}

However, the condition editor doesn't display a matrix in a list of available form elements: