This maintenance release fixes a few problems revolving around 3D/contour plotting, and hotlinking files.

• RESOLVED: could not create a 2D contour plot when the current dataset was empty. Fixed. [4123]
• RESOLVED: If a hotlink was created to a nonexistent file, the graphs were put in INVALID model, and they never recovered Fixed. [4128]
• RESOLVED: Changing the number of columns in a hotlinked file is now not allowed. [4130]
• RESOLVED: Graph malfunctions when selecting File->New and setting the number of independent variables to 2. Fixed. [4120]
• RESOLVED: Starting with a zero sized dataset, adding data points does not update properly on a contour plot. Fixed. [4124]
• RESOLVED: if a hotlinked 3D dataset is cut back to an empty file, indeterminate results. Fixed. [4129]
• RESOLVED: Strange behavior from colorbar if a 3D plot (or contour plot) consisted of all constant z values. Fixed. [4131]