Add an inset plot by interactively zooming into a plot.

PURPOSE:
This app can be used to add an inset layer to your graph by interactively zooming into a data plot. A rectangular region of interest tool is provided to decide what data range of the original plot should appear in the inset layer. A connector line can also be added between the ROI and the inset layer.
Note: The tool only works on 2D graphs with Cartesian coordinate system.

INSTALLATION:
Download the Zoomed Inset.opx file and then drag and drop onto the Origin workspace. A new app icon will be added to Apps gallery window.

OPERATION:

1. Activate the 2D graph and press the icon from the Apps gallery to open the dialog.
2. In the dialog, you can customize the rectangle ROI, and opt whether to add a connector line between the ROI and the Inset layer.
3. Click the OK button. The ROI and inset layer will be added to the graph.
4. Move and/or resize the ROI to select the part of plot you want displayed in the inset layer. You can also move or resize the inset layer to the desired position within the graph.
5. To delete the ROI and the connector line, select and press delete. 

Note: For the support of graph with multiple layers, it needs these layers in graph to be linked together, and then the first layer is activated.

v1.1: support graph with multiple layers
v1.2: add hint dialog for invalid graph or invalid plot