#1 Bug in the slope extraction tool: Plot disappears

[Alois]

Version beta0.42: Ubuntu 14.04.1 LTS and Win7

The plot disappears upon repeated usage of the slope extraction tool.

To reproduce:

Start the program. Hit Tools -> Slope Extraction.
Draw a line by left and right click in the plot area.

Add the line.

Close the tool.

Load another data file.

Bring up the slope extraction tool again. Now again add a line.

Close the dialog.

Again select the Slope Extraction tool.
The plot area turns white.