Description of problem:
If you try to change the properties for a device, say the processor temperature ranges, to assign the colours for different temperature triggers the applet 'freezes'

Version-Release number of selected component (if applicable):
Mate-Sensors-Applet 1.10.0

How reproducible:
Open preferences in mate-sensors-applet -->  choose sensors -->  choose a device (HD, CPU, Fan etc...) -->  select properties  -->  You can't change the values or close the properties box.

Steps to Reproduce:
1.  As above
2.
3.

Actual results:
Unable to change properties values.

Expected results:
Should be able to change properties values.

Additional info:
None