How to replace Application Launcher icon in Kubuntu (replace the "K" one with anything else)?

Question

I want to customize my KDE desktop. Firstly I want to replace an annoying letter "K" in a Menu. For example:

I supposed that it changes by editing some *.css files. For instance gnome-shell has /usr/share/gnome-shell/theme/gnome-shell.css. But I do not see anything like that in /usr/share/kde4/apps/desktoptheme/default/.

Also I tried to copy /usr/share/kde4/apps/desktoptheme/ to ~/.kde/share/apps/desktoptheme/ and to replace icons/kpackagekit.svgz with my own icon, but it didn't work.

So, how to change it? How to change this little thing? Should I copy something to somewhere and edit any CSS file? Or...

UPD. My system information:

DISTRIB_ID=Ubuntu
DISTRIB_RELEASE=18.04
DISTRIB_CODENAME=bionic
DISTRIB_DESCRIPTION="Ubuntu 18.04.1 LTS"
NAME="Ubuntu"
VERSION="18.04.1 LTS (Bionic Beaver)"
ID=ubuntu
ID_LIKE=debian
PRETTY_NAME="Ubuntu 18.04.1 LTS"
VERSION_ID="18.04"
HOME_URL="https://www.ubuntu.com/"
SUPPORT_URL="https://help.ubuntu.com/"
BUG_REPORT_URL="https://bugs.launchpad.net/ubuntu/"
PRIVACY_POLICY_URL="https://www.ubuntu.com/legal/terms-and-policies/privacy-policy"
VERSION_CODENAME=bionic
UBUNTU_CODENAME=bionic

UPD2.

are you on Kubuntu 18.04 or Ubuntu 18.04 to which you've added some "KDE" stuff?

Initially I installed Ubuntu 18.04, then in terminal I installed kubuntu-desktop

sudo apt install kubuntu-desktop

When I click on "K", I see a menu:

Solution 1

What you have posted in the image is the Application Launcher (aka Kickoff) widget (part of the desktop that can be removed or added) and comes as the default launcher: you just want to change its icon. (There are alternative launchers though; see "Alternatives" after right clicking the widget.)

The icon of that widget depends on the desktop theme: System Settings - Workspace theme - Desktop theme.

The one with K is that of the Kubuntu desktop theme, changing to Breeze presents you with a different icon:

(I think I have a bug: sometimes I need to restart the desktop (killall plasmashell; plasmashell &) to see that change.)

But you also can change the icon without changing the theme: Right click on the widget and select "Application Launcher Settings", then "Appearance", and click the icon button there.

Then select "choose".

The choice is large, you can select by category or from "All" or (from "Other icons") any icon file you have.

---

Note that changing manually the icon has the following consequences:

• that change will affect all desktop themes (all desktop themes will use the same custom icon)

• after that change you will not be able to easily restore the default icon.

In order to get back the default icon (specific to each desktop theme) you have to

• find it manually - which is difficult (for the Breeze desktop theme I have found it - or an almost identical one - under System Icons: Places - start-here-...), and even then, the one selected will affect all desktop themes,

or

• remove the Application Launcher widget from the panel (widgets have to be unlocked) and then add it again. (In this case the new Application Launcher may not start with the Super key anymore; to restore that, right click it, select "Application Launcher Settings - Keyboard Shortcuts", and there select Super-F1; after that, the launcher will be shown with Super key alone.)

Solution 2

1. Right click on the "K" (as I can see in your screenshots, it's the icon for an Application Launcher, which is in the panel).
2. In the contextual menu, click on "Application Launcher Settings".
3. Click on the icon button and click on "choose".
4. Select the icon of your preference and accept the changes.

Comments

[Sergey Mishin]

@PRATAP yes. 18.04.

[Sergey Mishin]

@DKBose didn't know that kubuntu and ubuntu + kde4 shell are different things. Sorry about that. I've added info to the question.

[DK Bose]

1:No need to be sorry! Please enter kinfocenter in the search box (in your second image). You'll see information there about what you have. 2: contd ...

[DK Bose]

Open System Settings, Look and Feel. You should see three options, Breeze, Breeze Dark, and Kubuntu. I suspect you're on Kubuntu which gives you the "K" icon. Try Breeze or Breeze Dark; they'll provide something else looking like this.

[DK Bose]

And at the bottom right of the Look and Feel window, you can "get new looks".

[Admin]

The default icon of Application Launcher is determined by the Workspace Theme - Desktop Theme. Note that changing the default icon with a custom one will affect all desktop themes and after this change all desktop themes will use the same custom icon.

[David O'Sullivan]

@SergeyMishin - Note that the other answer only mentions changing the icon manually (which affects all desktop themes) and doesn't specify a way to go back to the default icon (different for each desktop theme). See that in my answer.