A common operation is to change the colour of a plot. For this we use the colour selector dialogue shown below. The three sliders control the red, green, and blue intensities to use in producing the desired colour. The shaded box at the bottom illustrates the current colour. In some displays this will also interactively update the colour in the associated plot simultaneously.
Pressing the "OK" button will quit the colour selector and update the appropriate colours in the plot. Pressing "Cancel" will quit the colour selector without making any changes to the plot. Note that some colour dialogues may also be combined with extra controls for adjusting other graphical styles, such as the line width.
Many programs have a "Colours" command in the Options menu. This displays two colour selectors; one for each of the foreground and background colours. This can be used to adjust the main colour scheme used for the program. Pressing "OK" selects this colour scheme and keeps it in use until the program exits. Pressing "OK Permanent" accepts this colour scheme, but also updates the `$HOME/.tk_utilsrc' file. This means that the colour scheme will be used for all future program uses. To revert to the default colours, manually edit the `$HOME/.tk_utilsrc' file.