**BUG** Concise problem statement: As the image <http://i.imgur.com/PC0GIRH.png> shows it is possible to click on a data point in a WaveForm trace and then accidentally drag it away from the trace. This is not good for two reasons: (i) accidentally clickin on a data point on a trace causes the whole trace to highlight because all the data points highlight; (ii) it is possible to accidentally drag the selected point away from it's correct position. It is especially easy to accidentally select a data point in a plot of a large dataset when using the click-and-drag cursor movement. The changes made this way are not permanent: they do not appear in a saved copy and so can not be exported but tis may confuse users. Is there a way to stop this happening? Steps to reproduce bug: 1. Run a sim that generates a plot in WaveForm; 2. Click close to the trace until it highlights purple then drag a datapoint away from the trace. Results: As shown in the uploaded image. Expected results: It should not be possible to edit the traces once plotted. Url: plot cannot be saved. Browser: Chrome on WinXP