Thanks, Magdalena Dembna, But there are some bugs in this component:

1. Use your left button on your mouse to click on select and move your cursor to another place without raising your finger from the left button. Now you can use select as input
2. Click on select, then click on "select all" and then click on "select all" again. The second value still selected.

You can see these problems in your components examples: https://vue.mdbootstrap.com/#/forms/pro/multiselect (but in the docs everything is correct).

Both :show property and @toggleSelect are optional - the purpose behind is that the save button is no longer inside select itself. If you're not using this button, just the default select component, you don't need to use those. The import of mdbBtn was missing from the snippet, my fault:

<template>
  <mdb-select
    multiple
    search
    selectAll
    v-model="multiOptions"
    label="Example label"
    :show="showSelect"
    @toggleSelect="showSelect = $event"
  >
    <template #footer>
      <mdb-btn class="mt-0 ml-2 mb-3" @click="showSelect = false" color="primary" size="sm">Save</mdb-btn>
    </template>
  </mdb-select>
</template>

<script>
  import { mdbSelect, mdbBtn } from 'mdbvue';

  export default {
    components: {
      mdbSelect, mdbBtn
    },
    data() {
      return {
        showSelect: false,
        multiOptions: [
          { text: 'Option nr 1', value: 'Option 1' },
          { text: 'Option nr 2', value: 'Option 2' },
          { text: 'Option nr 3', value: 'Option 3' },
          { text: 'Option nr 4', value: 'Option 4' },
          { text: 'Option nr 5', value: 'Option 5' }
        ],
      }
    }
  };
</script>

Basic version, without the save button would look like this:

<template>
  <mdb-select
    multiple
    search
    selectAll
    v-model="multiOptions"
    label="Example label"
  >
  </mdb-select>
</template>

<script>
  import { mdbSelect } from 'mdbvue';

  export default {
    components: {
      mdbSelect
    },
    data() {
      return {
        showSelect: false,
        multiOptions: [
          { text: 'Option nr 1', value: 'Option 1' },
          { text: 'Option nr 2', value: 'Option 2' },
          { text: 'Option nr 3', value: 'Option 3' },
          { text: 'Option nr 4', value: 'Option 4' },
          { text: 'Option nr 5', value: 'Option 5' }
        ],
      }
    }
  };
</script>

If still none of those is working for you, I need to ask you gain for screenshot of the console. Have you updated your main.js after the version update?

I have tried your code and it doesn't work:

<template>
  <mdb-select
    multiple
    search
    selectAll
    v-model="multiOptions"
    label="Example label"
    :show="showSelect"
    @toggleSelect="showSelect = $event"
  >
    <template #footer>
      <mdb-btn class="mt-0 ml-2 mb-3" @click="showSelect = false" color="primary" size="sm">Save</mdb-btn>
    </template>
  </mdb-select>
</template>

<script>
  import { mdbSelect } from 'mdbvue';

  export default {
    components: {
      mdbSelect
    },
    data() {
      return {
        showSelect: false,
        multiOptions: [
          { text: 'Option nr 1', value: 'Option 1' },
          { text: 'Option nr 2', value: 'Option 2' },
          { text: 'Option nr 3', value: 'Option 3' },
          { text: 'Option nr 4', value: 'Option 4' },
          { text: 'Option nr 5', value: 'Option 5' }
        ],
      }
    }
  };
</script>

I have no problem on 5.8.3 with it...

And one more question:

Do I really need to handle open/close by myself? Why? I have 20 elements on the page like this and that won't be so easy as before.

Try the following code:

    <template>
        <mdb-select multiple search selectAll v-model="multiOptions" label="Example label" :show="showSelect" @toggleSelect="showSelect = $event">
                <template #footer>
                    <mdb-btn class="mt-0 ml-2 mb-3" @click="showSelect = false" color="primary" size="sm">Save</mdb-btn>
                </template>
        </mdb-select>
    </template>
    <script>
    import { mdbSelect } from 'mdbvue';

    export default() {
        data() {
            return {
            showSelect: false,
            multiOptions: [
                { text: 'Option nr 1', value: 'Option 1' }, 
                { text: 'Option nr 2', value: 'Option 2' }, 
                { text: 'Option nr 3', value: 'Option 3' }, 
                { text: 'Option nr 4', value: 'Option 4' }, 
                { text: 'Option nr 5', value: 'Option 5' }
              ],
            }
        }
    }
</script>

It seems to work fine in our demo app as well with v-model as with options. Save button is no longer included in the new mdb-select syntax - you need to use named slot. Complete list of properties can be found here: https://mdbootstrap.com/docs/vue/forms/multiselect/#v-3 in the API tab. If it still doesn't work, include screenshots of the console errors. Kind regards, Magdalena