Delete button in Core Build launch configuration does not delete all settings.

[jonahgraham]

Originally posted by @jonahgraham in #1090 (comment)

What is the purpose of the Delete button? It seems strange to locate this in the button bar.

As @DangMinhTam382 mentioned, not directly related to this PR, but the delete button is to match the Delete option in the big Debug Configurations GUI:

There is also a Duplicate sometimes for the same reason.

The logic of when to display them is in LaunchBarLaunchConfigDialog.createConfigButtons(Composite)

This area was most recently updated in https://bugs.eclipse.org/bugs/show_bug.cgi?id=560554 and interestingly that button can show Delete or Restore Defaults. Restore Defaults make be more appropriate verbiage for CMake configs?

However, when reopen "Edit configuration", previous settings are kept.

This is sort of correct. The Delete button deletes only the launch configuration, not the C build configuration. So pressing Delete (Restore Defaults) restores the defaults for Main, Arguments, and GDB tabs because those are stored in the .launch file. But it doesn't restore defaults for the build settings because they are stored in preferences.

[jld01]

Thank you for the explanation, @jonahgraham.