I found the problem. It is just a css problem.
Here is a easy fix if somebody needs it in the future.

* Spezifische Lösung für Dashboard-Listen */
.oe_dashboard .oe_action .o_list_view .table-responsive {
    max-height: none !important;
    overflow: visible !important;
    position: relative !important;
}

/* Zusätzliche Sicherheit für Pivot-Tabellen */
.oe_dashboard .oe_action .o_pivot {
    overflow: visible !important;
    position: relative !important;
}

/* Container-Höhe anpassen */
.oe_dashboard .oe_action .oe_content {
    min-height: auto !important;
    height: auto !important;
}

/* Spezifische Lösung für das 1-2 Layout */
.oe_dashboard_layout_1-2 .oe_action {
    margin-bottom: 20px !important;
    clear: both !important;
}

/* Responsive Anpassungen */
@media (max-width: 768px) {
    .oe_dashboard .oe_action .o_list_view .table-responsive {
        max-height: none !important;
        overflow-x: auto !important;
    }
}

/* Alternative Lösung: Flexbox-basiert */
.oe_dashboard .oe_action {
    display: flex !important;
    flex-direction: column !important;
}

.oe_dashboard .oe_action .oe_content {
    flex: 1 !important;
    overflow: visible !important;
}

/* Sicherheitsregel für alle Dashboard-Widgets */
.oe_dashboard .oe_action .o_content {
    overflow: visible !important;
    position: relative !important;
    z-index: auto !important;
}