Tutorial: Extending the KDE Panel

Matthias Elter has written a tutorial (print version; example source tarballs) on developing panel applets for Kicker, the KDE 2 panel. Kicker is a complete rewrite from the KDE 1 panel; this was done mainly to increase the panel's extensibility. KDE 2.0 introduced the panel applet API and KDE 2.1 added the panel extension API. The tutorial teaches you how to implement a simple panel applet using the panel applet API. From the tutorial: "Both the applet and extension APIs are simple. This qualifies writing a panel applet as
a suitable task for an introduction to KDE programming."


can someone please help me with a problem that I have with the extension child panel. I dislike the extension taskbar panel but i get my desired result when i use a child panel with the taskbar applet enabled. Problem is that everytime I restart KDE the applet does not start with the panel. I have to add it everytime. Anyhelp on how to get the taskbar applet to start with the child panel when i load KDE.


By Anthony Lander at Tue, 2001/05/01 - 5:00am

try adding it to your /usr/bin/startkde or ~/.kde/Autostart directory

By fix at Tue, 2001/05/01 - 5:00am

What command do I add to the "startkde" script. I need a command that would start the child panel applet at the top of my screen with a taskbar applet running in it.

By Anthony Lander at Wed, 2001/05/02 - 5:00am

I made up a quick shell script to do this.. it only handles one child applet right now and uses DCOP to add the applet. Just take the shell script at the end of this post and save it in /usr/bin/ (or wherever else you want it) and then edit /yourhomedir/.kde/share/config/kickerapplets and add the .desktop files one by one.. mine looks like


Then put an entry in your Autostart folder or /usr/bin/startkde to call 'sh /usr/bin/' and your done.

Does anyone have any hints as to how to set the initial size and position of applets? this is the only annoying thing left.. all my applets get crammed on the left side of the screen.

----- begin sh script

childDCOPid=`dcop kicker|grep ChildPanel`
echo "ChildPanel DCOP id is: $childDCOPid"

for i in `cat $appletfile`
echo "Adding $i to $childDCOPid"
dcop kicker $childDCOPid addApplet $i t
-----end sh script

By Hitesh Patel at Sat, 2001/05/05 - 5:00am

Wow... that kfifteenapplet is indeed very useless but addicting
Will it be in 2.2?

By Proton at Thu, 2001/05/03 - 5:00am

This is bug #23234, and debian bug #93006 ( ). I found the problem and submitted a patch to Debian, which AFAIK is in the latest Debian packages in their pool (hence that Debian bug is marked closed). I don't know whether anyone's sent it "upstream" yet.

If anyone's interested, here's the (very small) patch to fix it. Someone just forgot to call _containerArea->init() in the ChildPanelExtension constructor, so it doesn't load the settings. Looking at the files shows it's fine saving them.

Chris Boyle
Winchester College

By Chris Boyle at Fri, 2001/05/04 - 5:00am

Is it an applet?
If so then under preferences on the panel (right click) click the applets tab, and make sure that that applet is trusted and loads internally. This assumes that you trust it of course...

By Lo Wang at Sat, 2001/12/08 - 6:00am

can anyone tell me what are the files responsible for the panels ............

like if I want to modify the panel for all users before making the installation CD....... here i am trying to make a knoppix based distribustion.

Thanks in advance

By linneighborhood at Tue, 2005/08/09 - 5:00am

Ahhh, very nice. I've written a few applets and I quite like the API. What's stopped me from releasing them was the stuff, which the tutorial talks about.

Coming soon to a KDE application page near you:



By Ernie at Tue, 2001/05/01 - 5:00am

Can anyone show me how to add the Show Desktop applet to the quick launch applet, since it saves panel space.

By Asif Ali Rizwaan at Tue, 2001/05/01 - 5:00am

Configure Panel --> Add --> Desktop Access

By HGG at Wed, 2001/05/02 - 5:00am

Can anyone tells me how to run the thing is launch when I click on the "Desktop Access" Button.

I have a extended keyboard (with special key, and with lineakd i can run kcalc, netscape, etc...) but I want to assigne a special key to "Desktop Access" (like CTRL+ALT+D)

Any idea ?


By BRACH at Tue, 2003/03/25 - 6:00am

CTRL+ALT+D already works for me by default. You can change it in the Global Shortcuts menu under Panel->Toggle Showing Desktop.

By Navindra Umanee at Tue, 2003/03/25 - 6:00am

Can someone make the panel do what GNOME's does in terms of not having to go all the way across all three of my monitors at 1600x1200? That behavior really sucks.

By Johna at Wed, 2001/05/02 - 5:00am

I agree on this one, I have a widescreen 16x10 monitor where running at 1920x1280 wastes a lot of space along the taskbar.

By Ben Meyer at Wed, 2001/05/02 - 5:00am

Ask and ye shall recieve! Actually, the KDE developers are one step ahead of you - its been in CVS for a while (which means it'll be in 2.2), along with the ability to have only one panel-hider button instead of two, a couple more panel applets, faster Konqeror, more and better window decorations (IceWM theme importer!), more KControl modules (and improvements to existing ones, such as the screensaver module - now I have almost *twice* as many screensavers available!), more bugfixes, IMAP in KMail, and more! Everything people have been asking for and some stuff that they haven't even thought to ask for yet!

Hee hee hee... I love having CVS! Go KDE!

By not me at Wed, 2001/05/02 - 5:00am

Now if you could also be able to hide it on individual virtual desktops like you could with kpanel. I like kicker, but I don't need it on every desktop...

By anon at Wed, 2001/05/02 - 5:00am

could there be a clock in the mac style menu bar?

By horst at Wed, 2001/05/02 - 5:00am

One thing I was wondering about is whether KDE applications can be extended in the same fashion as third-parties manage to extend Microsoft Office and especially Internet Explorer.

Just look how deeply the Internet Explorer Powertools (or however they called this extensions pack) manages to hook into IE. Copernic's ( search tools also manage to plug into all of IE's context-menus, allowing you to perform a search of any word inside the page you're seeing (not to mention integrating into the toolbar and menus).

My credit card company has recently begun offering disposable credit card numbers, which are generated and filled-in simply by clicking a button on the IE toolbar. Assuming they wanted the feature for Linux as well, would they have an actual ability to build it?

By Toastie at Wed, 2001/05/02 - 5:00am

My credit card company has recently begun offering disposable credit card numbers, which are generated and filled-in simply by clicking a button on the IE toolbar. Assuming they wanted the feature for Linux as well, would they have an actual ability to build it?

In a word - yes. In fact, you can add a tool to any properly written KDE application, not just Konqueror.

There was even a tutorial posted to the dot recently (that created a HTML Validator), that immediately spawned a Babelfish translator plugin and quick Java/Javascript/cookie configure plugin. See for more information.


By Evan "JabberWok... at Wed, 2001/05/02 - 5:00am

Is it possible to configure kicker in order to use different panel applets for different virtual desktops ?

Thanks again for KDE

By xavier at Wed, 2001/05/02 - 5:00am

A propos panel, is it still possible to swallow
apps in the panel?

I found some documentation about using
.kdelnk files for swallowing apps but this
never worked for me with KDE 2.x.

Any help?

By Oliver Tonet at Wed, 2001/05/02 - 5:00am

When I log out from kde some settings (I mean child panel applets and some changes to the icons of application button) are lost. Every time.
I use Mandrake 8.0 and kde-2.1.1
Any suggestion is appreciated.

By striscio at Thu, 2001/05/03 - 5:00am

It's great to see the improvements in kicker (as well as all other parts of KDE!), but would it be out of line to suggest making it more GNOME-like, in terms of flexibility sometime in the future? Recently I played around a bit with the GNOME panel, and was really impressed. Some of the features I'd like to see eventually:

1. No distinction between "child" panels and the main panel. Right now, it's kind of awkward to work with the child panel, and it doesn't work quite the same as the main one (And IIRC you can only have one child panel onscreen).

2. More mobility. Allow panels to be positioned along any edge or corner of the screen; improve resizability (I'm using a CVS version right now that allows short panels, but it's a little buggy); perhaps the ability to slide them around easily.

3. Some way to group items in "sub-panels." I'd like to see a scenario like this: Say I want to put lots of app buttons on a panel, but I want some to be small and some large. I could create a sub-panel object to hold, say, the small icons, and that object would rest on the panel. The subpanel would work pretty much like a regular panel: you could configure it to show large/small/medium icons and other things like that.

4. Better taskbar and/or kasbar. It'd be nice to be able to configure it to "group" windows by certain criteria (window caption, class, etc.) so that all windows of a group would only show up as one item on the taskbar; then clicking on that button would pop up a menu of the actual windows.

5. Ability to edit and move menu items right in the menus, like in Win98 and above. In my experience it saves a lot of time not having to open a menu editor app.

My 2c.

By Rakko at Wed, 2001/05/09 - 5:00am

I agree with the suggested improvements.

A workaround for #5 which may save you some time, is to drag a shortcut to the panel, make the changes from there, then remove the extra shortcut. It adds two extra steps, but still saves considerable time compared to loading a menu editor and trying to find the right item again.

By Warren E. Downs at Thu, 2001/05/10 - 5:00am

There is a fair contingent of windows users that never edit their menus and aren't aware that they can do so.

I've noticed users who migrate quickly cotton onto how to do it with kde and lots of those use that knowledge to improve their menus at some point.

I think that how things are now is pretty usable.

In place editing would be a boon perhaps, but it shouldn't replace what we have now entirely.

KDE is highly configurable, it's the main strength of KDE over any other DE because no other DE does it in such a mature and easy-to-use way.

Let's not start limiting everything and obfuscating functionality to make things appear simpler (until you want to configure anything, that is).

HCI guidelines that go down that road are tosh.

By Gorky at Tue, 2005/12/06 - 6:00am

Does anyone knows how to get the gnome panel applets to work on KDE? Like I want this XMMS applet which is on gnome panel to work on KDE.

By Anup at Fri, 2003/08/01 - 5:00am

I've tried to see the tutorial but the link doesn't work. I know this is an old tutorial but I need to learn to programme applets for KDE panel.

My email is [email protected]

By Dani at Mon, 2007/03/12 - 5:00am