The latest version of Construct 3 implemented a UI for changing the colour of fonts and background in the event sheet (for a group or comment). This has given extra functionality such as hex colours, but removed the previous functionality of saving a number of custom colours, to create a custom colour palette.
Under the new system, to re-use a custom colors I have to write the RGB or hex values down by hand and type them in manually each time.
It would be great to have the ability back to create a custom palette, but a simple solution would be to allow copying and pasting a colour (e.g. hex value).