Some problems occurred when opening a file by double click

[appolloford]

This is caused by PR #181.
When opening a file by double click at the first time, the cursor cannot display the information normally. At the same time, the function of region will be blocked.

[kswang1029]

double-click to open an image will not be a feature in the new version. There should be buttons for users to select which mode to render such as raster, contour, vector, marker, etc. please consider to revert the commit if this part of code will be reused in the new version.