A hotkey feature to open the clipboard history has been available in Diodon since its very first version and is a major part of its usability. Unfortunately this hotkey has not always worked as expected, causing issues on certain desktop environments or stopped working altogether caused by regressions of updated libraries. Furthermore did customization of the hotkey not always work like when using Symbols or sometimes even the order how the keys were pressed mattered. All in all has this feature not been very stable. The main underlying problem for this is that there is no standard across desktop environments to register global hotkeys.
Looking at all those issues it is kind of obvious that handling of a hotkey should not be the responsibility of Diodon but be handled by the desktop environment itself. Therefore the decision has been made to drop the internal Diodon hotkey feature altogether as per version 1.4.0. Instead does a custom shortcut need to be registered through the settings offered by whatever desktop environment you use.
For GNOME/Unity this can be done by opening Keyboard app through the Dash/Activities overview. There you go to Shortcuts -> Custom Shortcuts and add a new one with the name “Diodon” and command “/usr/bin/diodon”. Afterwards assign your preferred hotkey and you are done.
If you are experiencing a hotkey issue with the current Diodon version you use you can already do this.
Unfortunately for Diodon at this point it is not possible to register this Custom Shortcut during package installation. So as of version 1.4.0 registration of a hotkey needs to be done manually. Additionally will also the special keybinding to browse through the history not work anymore as Diodon doesn’t know anymore what keybinding was used. (Of course you can still use the up and down keys to cycle through the history.)
We believe though the additional stability in the hotkey feature it makes up for this one-time manual step. Also we are working together with upstream of the different DEs so hopefully in future versions of Diodon this custom shortcut registration can also be done automatically during package installation again.
If you have any questions or concerns about this change leave a comment – feedback is always appreciated. And if you actually know a way how an application could register a custom shortcut during installation best have a look at this question.