Yes, that's quite a conundrum, but with your words you have inspired me to further testing and so I got the solution.

I removed require('bootstrap'); in my app.js. Thats all.

I think you´re right with your supposition of overlapping classes. I think bootstrap is part of mdb and does´nt have to be added extra.

So thank you for your daylie inspiration to solve this problem. <3

Hey thanks a lot for your time!

Iam using the mdbvue pro version 5.8.3 (actual git repo) in an firefox or chrome browser.

But i think i can specify this problem. Each time I open the dropdown-menu, an error appears in the console: TypeError: popper is null

But if i manually try to call the popper, it works:

The line in my bundle.js in which the error occurs is: popper.setAttribute('x-placement', placement);

I use Laravel 6 with Webpack:

bootstrap.js

try {
    window.Popper = require('popper.js').default;
    window.$ = window.jQuery = require('jquery');

    require('bootstrap');
} catch (e) {}

webpack.mix.js

mix.js('resources/js/app.js', 'public/js').sourceMaps()
   .js('resources/js/app/bundle.js', 'public/js/bundle.js').sourceMaps()
   .sass('resources/sass/app.scss', 'public/css');

Btw: it does not matter if i require window.Popper or window.popper

Thank you for dealing with my problem - :*

@Magdalena Dembna thank you for your answer. Here is the minified version of my code:

Template:

<template>
    <draggable class="row" v-model="testarray" >
        <mdb-col xl="3" md="6" class="mb-r" v-for="(test, index) in testarray" :key="index">
            <mdb-dropdown>
                <mdb-dropdown-toggle slot="toggle">Basic dropdown</mdb-dropdown-toggle>
                <mdb-dropdown-menu>
                <mdb-dropdown-item>Action</mdb-dropdown-item>
                <mdb-dropdown-item>Another action</mdb-dropdown-item>
                <mdb-dropdown-item>Something else here</mdb-dropdown-item>
                <div class="dropdown-divider"></div>
                <mdb-dropdown-item>Separated link</mdb-dropdown-item>
                </mdb-dropdown-menu>
            </mdb-dropdown>
        </mdb-col>
    </draggable>
</template>

Script:

<script>
    import draggable from "vuedraggable";
    import { mdbDropdown, mdbDropdownItem, mdbDropdownMenu, mdbDropdownToggle, mdbRow, mdbCol } from 'mdbvue'

    export default {
        components: {
            draggable,
            mdbRow,
            mdbCol,
            mdbDropdown,
            mdbDropdownItem,
            mdbDropdownMenu,
            mdbDropdownToggle
        },
        data() {
            return {
                testarray: [{"name": "name1"},{"name": "name2"},{"name": "name3"}]
            }
        }
    }
</script>

For testing you have to install vuedraggable: (source: vuedraggable git)

yarn add vuedraggable

npm i -S vuedraggable

@Tenarius can you share your code including entire structure with v-for directive so I could recreate your issue? I have simple snippet combining v-for with mdbDropdown and it seems to work fine:

<div v-for="key in 4" :key="key">
      <mdb-dropdown >
        <mdb-dropdown-toggle color="dark" slot="toggle">Material dropdown</mdb-dropdown-toggle>
        <mdb-dropdown-menu color="dark">
          <mdb-dropdown-item href="#">Action</mdb-dropdown-item>
          <mdb-dropdown-item href="#">Another action</mdb-dropdown-item>
          <mdb-dropdown-item href="#">Something else here</mdb-dropdown-item>
          <div class="dropdown-divider"></div>
          <mdb-dropdown-item href="#">Separated link</mdb-dropdown-item>
        </mdb-dropdown-menu>
      </mdb-dropdown>
    </div>

I have the same problem.

I use the mdb dropdown in an v-for-iteration.

<mdb-dropdown>
    <mdb-dropdown-toggle slot="toggle">Basic dropdown</mdb-dropdown-toggle>
    <mdb-dropdown-menu>
        <mdb-dropdown-item>Action</mdb-dropdown-item>
        <mdb-dropdown-item>Another action</mdb-dropdown-item>
        <mdb-dropdown-item>Something else here</mdb-dropdown-item>
        <div class="dropdown-divider"></div>
        <mdb-dropdown-item>Separated link</mdb-dropdown-item>
    </mdb-dropdown-menu>
</mdb-dropdown>

At the first click, the dropdown opened and the toggle switch to true.
At the second click out of the dropdown-area, the toggle switch to false.
After that, nothing happens. The toggle does´nt switch anymore.

I have watched the toggle in the vue development tools.

data
    $route
        timer:null
        toggle:false <---

Hi there,

Can You share Your code with us? It will be much easier to fix Your issue.

Best regards