ng-pick-datetimer Calendar Shows Behind Dialog box

Solved

I have added this css on main style.scss

.cdk-overlay-container {
    position: fixed;
    pointer-events: none;
    top: 0;
    left: 0;
    height: 100%;
    width: 100%;
    display: flex;
    position: absolute;
    z-index: 9999999 !important;
}
.cdk-global-overlay-wrapper, .cdk-overlay-container {
    pointer-events: none;
    top: 0;
    left: 0;
    height: 100%;
    width: 100%;
    display: flex;
    position: absolute;
    z-index: 9999999 !important;
}

This is more than enough:

.cdk-global-overlay-wrapper, .cdk-overlay-container {
  z-index: 99999 !important;
}

Cheers.