Selection color is not visible on Yaru themes

[Migu]

Hello,

A few X11 programs use colors taken from Xresources (xrdb -query), among which those using FLTK (on X11, not Wayland) or Tcl/tk.

In these programs, if no other color has been explicitly defined, the selected texts are not distinguishable from the non-selected texts, which can make the program barely usable.

You can experiment this in Tcl/tk by saving, making executable and running the following lines (upper part uses “Entry” configuration, bottom part uses “Text” configuration: they can be set as different, but in MATE/Yaru themes both have invisible selections):

#!/usr/bin/wish
entry .en
.en insert 0 "Entry sample"
text .txt -height 2 -width 20
.txt insert 0.0 "Text sample"
pack .en .txt

A request was previously made to manually tweak the selection colors, by editing the file /usr/share/themes/YOUR_THEME/gtk-3.0/gtk.css . I cannot use it because the file /usr/share/themes/Yaru-blue/gtk-3.0/gtk.css is just an import, and I do not know how to change the original data:

@import url("resource:///com/ubuntu/themes/Yaru-blue/3.0/gtk.css");

This previous request:

How do I change selection rectangle color?

You should describe better your ask. It's not about selection from mouse. And after you use LFM word which is unknown by many of us. Do you want to change color of the rectangle selection from click mouse? For my knowledge, why do you want change it? On Ubuntu MATE, the color of the selection rectangle (rubber band) is controlled by the GTK theme. To change it, you need to modify the theme’s CSS file. Method 1: Modify the GTK Theme CSS File Find the active GTK theme Open a terminal and ru…

Anyway, the real problem is not about tweaking the colors: the problem is present in all MATE standard themes (Yaru-…), so there should be a general solution. Especially since there seems to be no user-friendly way to change these colors.

What happens: when a theme is selected, the program /usr/libexec/mate-settings-daemon sends to /usr/bin/xrdb -merge -quiet the following lines (only useful lines included), for Yaru-blue:

#define BACKGROUND #fafafa
#define FOREGROUND #3d3d3d
#define SELECT_BACKGROUND #fafafa
#define SELECT_FOREGROUND #3d3d3d
#define WINDOW_BACKGROUND #fafafa
#define WINDOW_FOREGROUND #3d3d3d
...

*Text.background: WINDOW_BACKGROUND
*Text.foreground: WINDOW_FOREGROUND
*Text.highlightBackground: WINDOW_BACKGROUND
*Text.highlightColor: WINDOW_FOREGROUND
*Text.activeBackground: WINDOW_BACKGROUND
*Text.activeForeground: WINDOW_FOREGROUND
*Text.selectBackground: SELECT_BACKGROUND
*Text.selectForeground: SELECT_FOREGROUND

As you can see, the values for SELECT_FOREGROUND/SELECT_BACKGROUND are the same as for FOREGROUND/BACKGROUND, hence the text selection is not visible.

My workaround so far is:

1. Create a ~/.Xresources with the following lines:

#define SELECT_BACKGROUND #4040c0
#define SELECT_FOREGROUND #ffffff
*Entry.selectBackground: SELECT_BACKGROUND
*Entry.selectForeground: SELECT_FOREGROUND
*Text.selectBackground: SELECT_BACKGROUND
*Text.selectForeground: SELECT_FOREGROUND
*Listbox.selectBackground: SELECT_BACKGROUND
*Listbox.selectForeground: SELECT_FOREGROUND
*Canvas.selectbackground: SELECT_BACKGROUND
*Canvas.selectforeground: SELECT_FOREGROUND

2. create a start-up task, with a delay of 5 seconds (because Xresources are overwritten by the theme), with command:

xrdb -merge /home/MYLOGIN/.Xresources

With this, I am happy, my system works correctly. But really, it is just a workaround.

[Bombilla]

Hi, @Migu and welcome to the Ubuntu MATE Community!