Mouse wheel does not work on terminator

[AA]

I am using Terminator 1.91 on Linux Mint 19.1.
The mouse wheel works on all apps (Firefox, Emacs, Xterm...) but not on Terminator, i.e I cannot scroll through the lines of terminator using the mouse wheel.
I do have a scrollbar on the right of the terminal.

I would guess this is a configuration issue, not a bug. But would very much like help on how to solve this :)

Note: it used to work on Linux Mint 18.3.

I attach my .config/terminator/config

When I use option -d, I get this:

[!515]$ ConfigBase::__init__: Borg::__init__: Preparing borg state for ConfigBase
noclass::get_config_dir: Found config dir: /home/axelle/.config
ConfigBase::load: looking for config file: /home/axelle/.config/terminator/config
ConfigBase::load: config validated successfully
ConfigBase::load: ConfigBase::load: Processing section: global_config
ConfigBase::load: ConfigBase::load: Processing section: keybindings
ConfigBase::load: ConfigBase::load: Processing keybindings: cycle_prev
ConfigBase::load: ConfigBase::load: Processing keybindings: help
ConfigBase::load: ConfigBase::load: Processing keybindings: close_window
ConfigBase::load: ConfigBase::load: Processing keybindings: group_tab
ConfigBase::load: ConfigBase::load: Processing keybindings: resize_left
ConfigBase::load: ConfigBase::load: Processing keybindings: broadcast_all
ConfigBase::load: ConfigBase::load: Processing keybindings: rotate_ccw
ConfigBase::load: ConfigBase::load: Processing keybindings: move_tab_left
ConfigBase::load: ConfigBase::load: Processing keybindings: go_right
ConfigBase::load: ConfigBase::load: Processing keybindings: new_tab
ConfigBase::load: ConfigBase::load: Processing keybindings: resize_right
ConfigBase::load: ConfigBase::load: Processing keybindings: resize_down
ConfigBase::load: ConfigBase::load: Processing keybindings: toggle_zoom
ConfigBase::load: ConfigBase::load: Processing keybindings: scaled_zoom
ConfigBase::load: ConfigBase::load: Processing keybindings: zoom_in
ConfigBase::load: ConfigBase::load: Processing keybindings: paste
ConfigBase::load: ConfigBase::load: Processing keybindings: full_screen
ConfigBase::load: ConfigBase::load: Processing keybindings: prev_tab
ConfigBase::load: ConfigBase::load: Processing keybindings: split_vert
ConfigBase::load: ConfigBase::load: Processing keybindings: ungroup_all
ConfigBase::load: ConfigBase::load: Processing keybindings: broadcast_off
ConfigBase::load: ConfigBase::load: Processing keybindings: cycle_next
ConfigBase::load: ConfigBase::load: Processing keybindings: rotate_cw
ConfigBase::load: ConfigBase::load: Processing keybindings: insert_number
ConfigBase::load: ConfigBase::load: Processing keybindings: insert_padded
ConfigBase::load: ConfigBase::load: Processing keybindings: zoom_out
ConfigBase::load: ConfigBase::load: Processing keybindings: broadcast_group
ConfigBase::load: ConfigBase::load: Processing keybindings: go_prev
ConfigBase::load: ConfigBase::load: Processing keybindings: layout_launcher
ConfigBase::load: ConfigBase::load: Processing keybindings: close_term
ConfigBase::load: ConfigBase::load: Processing keybindings: new_terminator
ConfigBase::load: ConfigBase::load: Processing keybindings: ungroup_tab
ConfigBase::load: ConfigBase::load: Processing keybindings: go_left
ConfigBase::load: ConfigBase::load: Processing keybindings: copy
ConfigBase::load: ConfigBase::load: Processing keybindings: hide_window
ConfigBase::load: ConfigBase::load: Processing keybindings: edit_tab_title
ConfigBase::load: ConfigBase::load: Processing keybindings: go_down
ConfigBase::load: ConfigBase::load: Processing keybindings: reset
ConfigBase::load: ConfigBase::load: Processing keybindings: search
ConfigBase::load: ConfigBase::load: Processing keybindings: go_up
ConfigBase::load: ConfigBase::load: Processing keybindings: resize_up
ConfigBase::load: ConfigBase::load: Processing keybindings: next_tab
ConfigBase::load: ConfigBase::load: Processing keybindings: split_horiz
ConfigBase::load: ConfigBase::load: Processing keybindings: zoom_normal
ConfigBase::load: ConfigBase::load: Processing keybindings: move_tab_right
ConfigBase::load: ConfigBase::load: Processing keybindings: new_window
ConfigBase::load: ConfigBase::load: Processing keybindings: edit_window_title
ConfigBase::load: ConfigBase::load: Processing keybindings: group_all
ConfigBase::load: ConfigBase::load: Processing keybindings: go_next
ConfigBase::load: ConfigBase::load: Processing keybindings: edit_terminal_title
ConfigBase::load: ConfigBase::load: Processing keybindings: reset_clear
ConfigBase::load: ConfigBase::load: Processing keybindings: toggle_scrollbar
ConfigBase::load: ConfigBase::load: Processing section: profiles
ConfigBase::load: ConfigBase::load: Processing profile: default
ConfigBase::load: ConfigBase::load: Processing section: layouts
ConfigBase::load: ConfigBase::load: Processing layouts: default
ConfigBase::load: ConfigBase::load: Processing section: plugins
Config::set_profile: Config::set_profile: Changing profile to default
Config::connect_gsetting_callbacks: GSetting connects for system changes
noclass::parse_options: OptionParse::parse_options: command line options: {'nodbus': None, 'classname': None, 'working_directory': None, 'select': None, 'fullscreen': None, 'layout': 'default', 'debug_classes': None, 'version': None, 'role': None, 'forcedicon': None, 'config': '/home/axelle/.config/terminator/config', 'profile': None, 'debug_methods': None, 'maximise': None, 'debug': 1, 'borderless': None, 'new_tab': None, 'hidden': None, 'dummy': None, 'execute': None, 'geometry': None, 'command': None, 'forcedtitle': None}
ConfigBase::load: ConfigBase::load: config already loaded
Config::set_profile: Config::set_profile: Changing profile to default
Config::connect_gsetting_callbacks: GSetting connects for system changes
ConfigBase::get_item: ConfigBase::get_item: dbus found in globals: True
function::with_proxy: dbus client call: new_window_cmdline
function::with_proxy: dbus client call: new_tab_cmdline
function::with_proxy: dbus client call: new_window
function::with_proxy: dbus client call: new_tab
function::with_proxy: dbus client call: hsplit
function::with_proxy: dbus client call: vsplit
function::with_proxy: dbus client call: get_terminals
function::with_proxy: dbus client call: get_window
function::with_proxy: dbus client call: get_window_title
function::with_proxy: dbus client call: get_tab
function::with_proxy: dbus client call: get_tab_title
DBusService::__init__: Borg::__init__: Preparing borg state for DBusService
DBusService::prepare_attributes: Checking for bus name availability: net.tenshu.Terminator20x1a6021154d881c
DBusService::prepare_attributes: bus name unavailable: net.tenshu.Terminator20x1a6021154d881c
noclass::<module>: Unable to become master process, operating via DBus
noclass::<module>: Requesting a new window

[AA (aafortinet)]

I solved the problem on my distro by installing imwheel: apt install imwheel.