I made some component for you using https://github.com/bleenco/ng2-datepicker this.
Install this depenencies lines,
date-fns
npm i date-fns
https://www.npmjs.com/package/date-fns
ngx-slimscroll
npm install ngx-slimscroll
https://www.npmjs.com/package/ngx-slimscroll
Here is an source in stackblitz. The sass property not supported in stackblitz. That's why output not displayed.You copy the ng-datepicker folder and past your project folder.
https://stackblitz.com/edit/angular-agvjhm
Add this line in app.module.ts file,
import { NgDatepickerModule } from '../app/ng-datepicker/module/ng-datepicker.module';
imports: [
NgDatepickerModule,
],
app.html file,
<ng-datepicker [(ngModel)]="date" [isOpened]="true">
<ng-datepicker-default [(ngModel)]="date">
use some br tag between this two tags. Because opened default first tag. So it's occupy some spaces and covered second tag.
Working Perfect tested, Here is some screenshot,

let try this once and let me know.
Edit:-(Please Check)
app.module.ts file
import { NgModule } from '@angular/core';
import { BrowserModule } from '@angular/platform-browser';
import { FormsModule } from '@angular/forms';
import { AppComponent } from './app.component';
import { HelloComponent } from './hello.component';
import { NgDatepickerModule } from './ng-datepicker/module/ng-datepicker.module';
@NgModule({
imports: [ BrowserModule, FormsModule, NgDatepickerModule ],
declarations: [ AppComponent, HelloComponent ],
bootstrap: [ AppComponent ]
})
export class AppModule { }
ng-datepicker.module.ts
import { NgModule } from '@angular/core';
import { CommonModule } from '@angular/common';
import { FormsModule } from '@angular/forms';
import { NgSlimScrollModule } from 'ngx-slimscroll';
import { NgDatepickerModifiedComponent } from '../ng-datepicker-modified/ng-datepicker-modified';
import { NgDatepickerDefaultComponent } from '../ng-datepicker-default/ng-datepicker-default';
@NgModule({
declarations: [ NgDatepickerModifiedComponent,NgDatepickerDefaultComponent ],
imports: [ CommonModule, FormsModule, NgSlimScrollModule ],
exports: [ NgDatepickerModifiedComponent,NgDatepickerDefaultComponent, CommonModule, FormsModule, NgSlimScrollModule ]
})
export class NgDatepickerModule { }
Iam added this lines only see.