Both these widgets are pop-up windows, but they have different purposes. If you want to create an alert, you can use the Popup widget. After a user clicks somewhere outside the Popup, it will disappear.
The Context widget, in its turn, can contain info or functionality which the user may need more than once. For example, a right click can trigger a short memo that describes how your app works.
Besides, you can place a frequently used component within Context. For example, if you want to create a graphical online application, the Context window may contain a Colorpicker.
The Context widget appears on the screen upon a right click. It can contain an HTML element or any Webix component. You can use it to provide users with on-demand explanatory information or give them easy access to frequently used functionality.
Popup has both modal and modeless states. In the modal state a popup prevents users from working with the application until they interact with it. A Modeless popup disappears from the screen when a user clicks outside it.
Size and Positioning
When you work with the Popup widget, you have to define its size and position. By default, this component will stick to the top-left corner. Webix allows you to set the width and height of the Popup and define its position relative to the top and left sides of the screen, or relative to another HTML element or Webix widget.
Any custom HTML object (image, text, etc.) or another Webix widget can be inserted into Webix Popup.
This widget can also be used for creating a popup menu that appears on a button click.