fix(styling): Column Header should always be on top of grid container (…

…#1578)

* fix(styling): Column Header should always be on top of grid container
- the use of `overflow: hidden` on the grid container made the Column Header to show as always in the limit of the grid container but in some cases our grid is smaller than the column header and that was a problem

packages/common/src/core/slickGrid.ts

@@ -645,7 +645,6 @@ export class SlickGrid<TData = any, C extends Column<TData> = Column<TData>, O e
     };
 
     emptyElement(this._container);
-    this._container.style.overflow = 'hidden';
     this._container.style.outline = String(0);
     this._container.classList.add(this.uid);
     this._container.classList.add('slick-widget');

packages/common/src/styles/slick-grid.scss

@@ -43,7 +43,6 @@
 }
 
 .slickgrid-container {
-  overflow: hidden;
   outline: 0;
   position: relative;
   box-sizing: content-box;