Minor issue when updating infinite wave colouring values

[simon.snake]

In the colour dialog, editing infinite wave colouring values, if I want to update a value, I have to first select which entry to update, then change the value of the period and then press the update button.  If I wish to edit the Period value again, I have to now re-select the entry in the list before editing the value a second time.

When trying to get an image looking nice by changing the values of the waves, this becomes tedious, and forgetting to reselect the entry in the list before changing the value does nothing when hitting the Update button.

In an ideal world, pressing update would do three things:

1) Update the currently selected line
2) Re-select that line
3) Give the focus back to the Period field.

Doing this step would make the whole process of changing the infinite waves much faster, and prevent frustration to users.

I suppose that you could also make adding a new wave better too, by:

1) Adding the new infinite wave entry into the list
2) Select this new line
3) Give focus back to the Period field.

I suppose that the code should also include logic that disables (greys out) the Update and Delete buttons when no line is selected from the list.

If you deem these issues not important enough that's fine, but if you feel they could help users of the software feel free to implement the changes.