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I use the XFCE4 desktop environment in my Linux distro. By default, when you minimize an application in XFCE4, its icon becomes dimmed on the taskbar. This is to indicate which windows are minimized with a quick glance at the taskbar. However, not everyone likes this behavior. Some users prefer to see minimized app icons in full color. While XFCE4 does not come with an option to disable the dimming of icons, there is a quick hack which will allow you to change the appearance of the minimized window icons.

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Here is how icons look like, by default:
XFCE4 default taskbar iconsAll minimized windows have a dimmed icon in the taskbar, while it is bright for active windows.

To change this behavior, you need to create a simple text file in your "home" directory, e.g.

/home/username
Just open your favorite text editor and paste the following text:

style "xfce-tasklist-style"
{

Lucency of minimized icons. Valid values are between 0 (completely

hide the icon) and 100 (don't lighten the icon).

XfceTasklist::minimized-icon-lucency = 100
}
class "XfceTasklist" style "xfce-tasklist-style"
XFCE4 gtkrcThese lines override the default appearance of taskbar icons in XFCE4. The parameter "minimized-icon-lucency" defines how much lightened the minimized app icon should be. If you set it to 100, the icon will not be changed when you minimize the app's window.

Save the file as .gtkrc-2.0 in your home directory.

Now, go to XFCE4's settings manager and pick the Appearance icon. Switch to some gtk theme: XFCE4 change gtk style 1

Then switch back to your previous theme: XFCE4 change gtk style 2

This causes the .gtkrc-2.0 file to be applied to your appearance settings.

Now, just restore and minimize back all your windows. The taskbar icons will not be dimmed anymore. XFCE4 taskbar icon not dimmed

You can read more details about gtkrc-2.0 tricks applicable to XFCE4 components in its official documentation.