Install Geany and its plugins
sudo add-apt-repository ppa:geany-dev/ppa sudo apt-get update sudo apt-get install geany geany-plugins
Activate needed plugins
Open Geany, go to Tools -> Plugin Manager and activate the plugins:
Enable “Mark Word” feature of the Addons plugin
Go to Tools -> Plugin Manager, select Addons and click on Preferences. Enable the option “Mark all occurences of a word when double-clicking it” on the Configure Plugins dialog.
Add color schemes to Geany
Follow the instructions on github.com/codebrainz/geany-themes for downloading and installing new schemes. Then go to View -> Change Color Scheme and select one.
Create custom color scheme
Make a copy of your favorite color scheme
cp ~/.config/geany/colorschemes/solarized-dark.conf ~/.config/geany/colorschemes/my-solarized-dark.conf
Open the new file in Geany, update the [theme_info] section, and modify the colors according to the Geany Manual, for example:
marker_line=0x000000;0xb8f4b8;false;false marker_search=0x000000;0xb8f4b8;false;false marker_mark=0x000000;0xb8f4b8;false;false
Get rid of the vertical line (long line marker)
Navigate to Edit -> Preferences, select Editor then the Display tab, and disable the Long line marker.