palemoon icon doubles

hi all,
i'm using former makulu core edition (xfce on debian testing) and till some updates ago everything was perfect, now it still is but for palemoon
if i rightclick on palemoon icon i haven't the option to keep it on the dock
if i start palemoon from plank icon it creates a second icon - as if i had none on the dock- and any new window i might open would add a blue dot under the second icon, and if i click on the docked icon it opens a brand new window

 $ plank --version
0.11.89

 $ plank -d
[DEBUG 09:34:33.908929] [GLib] unsetenv() is not thread-safe and should not be used after threads are created
[INFO 09:34:33.909524] [AbstractMain:229] Plank version: 0.11.89
[INFO 09:34:33.909559] [AbstractMain:230] Kernel version: 5.7.0-1-amd64
[INFO 09:34:33.909588] [AbstractMain:231] GLib version: 2.64.4 (2.60.6)
[INFO 09:34:33.909616] [AbstractMain:234] GTK+ version: 3.24.20 (3.24.10)
[INFO 09:34:33.909643] [AbstractMain:237] Wnck version: 3.32.0
[INFO 09:34:33.909677] [AbstractMain:238] Cairo version: 1.16.0
[INFO 09:34:33.909708] [AbstractMain:239] Pango version: 1.44.7
[INFO 09:34:33.909735] [AbstractMain:240] + Cairo/Gtk+ HiDPI support enabled
[INFO 09:34:33.909762] [AbstractMain:242] + Dynamic Quicklists support enabled
[INFO 09:34:33.909788] [AbstractMain:245] + XInput Barriers support enabled
[DEBUG 09:34:33.916281] [GLib-GIO] _g_io_module_get_default: Found default implementation gvfs (GDaemonVfs) for ‘gio-vfs’
[INFO 09:34:34.003373] [WindowControl:68] Window-manager: Xfwm4
[DEBUG 09:34:34.043667] [DockletManager:204] Loading module '/usr/lib/x86_64-linux-gnu/plank/docklets/libdocklet-applications.so'
[INFO 09:34:34.043852] [DockletManager:107] Docklet 'applications' registered
[DEBUG 09:34:34.045308] [DockletManager:204] Loading module '/usr/lib/x86_64-linux-gnu/plank/docklets/libdocklet-battery.so'
[INFO 09:34:34.045473] [DockletManager:107] Docklet 'battery' registered
[DEBUG 09:34:34.046866] [DockletManager:204] Loading module '/usr/lib/x86_64-linux-gnu/plank/docklets/libdocklet-clippy.so'
[INFO 09:34:34.047026] [DockletManager:107] Docklet 'clippy' registered
[DEBUG 09:34:34.048499] [DockletManager:204] Loading module '/usr/lib/x86_64-linux-gnu/plank/docklets/libdocklet-clock.so'
[INFO 09:34:34.048659] [DockletManager:107] Docklet 'clock' registered
[DEBUG 09:34:34.050032] [DockletManager:204] Loading module '/usr/lib/x86_64-linux-gnu/plank/docklets/libdocklet-cpumonitor.so'
[INFO 09:34:34.050191] [DockletManager:107] Docklet 'cpumonitor' registered
[DEBUG 09:34:34.051485] [DockletManager:204] Loading module '/usr/lib/x86_64-linux-gnu/plank/docklets/libdocklet-desktop.so'
[INFO 09:34:34.051642] [DockletManager:107] Docklet 'desktop' registered
[DEBUG 09:34:34.053087] [DockletManager:204] Loading module '/usr/lib/x86_64-linux-gnu/plank/docklets/libdocklet-trash.so'
[INFO 09:34:34.053245] [DockletManager:107] Docklet 'trash' registered
[DEBUG 09:34:34.053389] [GLib] setenv()/putenv() are not thread-safe and should not be used after threads are created
[DEBUG 09:34:34.077117] [GLib-GIO] _g_io_module_get_default: Found default implementation dconf (DConfSettingsBackend) for ‘gsettings-backend’
[INFO 09:34:34.077355] [AbstractMain:299] Running with 1 docks ('dock1')
[DEBUG 09:34:34.077456] [DockController:80] Create dock 'dock1' (config_folder = /home/carlo/.config/plank/dock1)
[DEBUG 09:34:34.077519] [GLib] setenv()/putenv() are not thread-safe and should not be used after threads are created
[DEBUG 09:34:34.077696] [Settings:53] Bind 'PlankDockPreferences' to '/net/launchpad/plank/docks/dock1/'
[WARN 09:34:34.219874] [Preferences:192] '/usr/share/plank/themes/Transparent/dock.theme' is read-only!
[DEBUG 09:34:34.219953] [Preferences:349] Loading preferences from file '/usr/share/plank/themes/Transparent/dock.theme'
[WARN 09:34:34.226554] [Preferences:378] Missing key 'OuterStrokeColor' for group 'PlankTheme' in preferences file '/usr/share/plank/themes/Transparent/dock.theme' - using default value
[WARN 09:34:34.226594] [Preferences:378] Missing key 'FillStartColor' for group 'PlankTheme' in preferences file '/usr/share/plank/themes/Transparent/dock.theme' - using default value
[WARN 09:34:34.226630] [Preferences:378] Missing key 'FillEndColor' for group 'PlankTheme' in preferences file '/usr/share/plank/themes/Transparent/dock.theme' - using default value
[WARN 09:34:34.226664] [Preferences:378] Missing key 'InnerStrokeColor' for group 'PlankTheme' in preferences file '/usr/share/plank/themes/Transparent/dock.theme' - using default value
[WARN 09:34:34.226694] [Preferences:378] Missing key 'HorizPadding' for group 'PlankDockTheme' in preferences file '/usr/share/plank/themes/Transparent/dock.theme' - using default value
[WARN 09:34:34.226746] [Preferences:378] Missing key 'ItemPadding' for group 'PlankDockTheme' in preferences file '/usr/share/plank/themes/Transparent/dock.theme' - using default value
[WARN 09:34:34.226775] [Preferences:378] Missing key 'IndicatorSize' for group 'PlankDockTheme' in preferences file '/usr/share/plank/themes/Transparent/dock.theme' - using default value
[WARN 09:34:34.226803] [Preferences:378] Missing key 'IconShadowSize' for group 'PlankDockTheme' in preferences file '/usr/share/plank/themes/Transparent/dock.theme' - using default value
[WARN 09:34:34.226853] [Preferences:378] Missing key 'UrgentBounceHeight' for group 'PlankDockTheme' in preferences file '/usr/share/plank/themes/Transparent/dock.theme' - using default value
[WARN 09:34:34.226910] [Preferences:378] Missing key 'LaunchBounceHeight' for group 'PlankDockTheme' in preferences file '/usr/share/plank/themes/Transparent/dock.theme' - using default value
[WARN 09:34:34.226945] [Preferences:378] Missing key 'FadeOpacity' for group 'PlankDockTheme' in preferences file '/usr/share/plank/themes/Transparent/dock.theme' - using default value
[WARN 09:34:34.226974] [Preferences:378] Missing key 'ClickTime' for group 'PlankDockTheme' in preferences file '/usr/share/plank/themes/Transparent/dock.theme' - using default value
[WARN 09:34:34.227000] [Preferences:378] Missing key 'UrgentBounceTime' for group 'PlankDockTheme' in preferences file '/usr/share/plank/themes/Transparent/dock.theme' - using default value
[WARN 09:34:34.227027] [Preferences:378] Missing key 'LaunchBounceTime' for group 'PlankDockTheme' in preferences file '/usr/share/plank/themes/Transparent/dock.theme' - using default value
[WARN 09:34:34.227052] [Preferences:378] Missing key 'ActiveTime' for group 'PlankDockTheme' in preferences file '/usr/share/plank/themes/Transparent/dock.theme' - using default value
[WARN 09:34:34.227077] [Preferences:378] Missing key 'SlideTime' for group 'PlankDockTheme' in preferences file '/usr/share/plank/themes/Transparent/dock.theme' - using default value
[WARN 09:34:34.227101] [Preferences:378] Missing key 'FadeTime' for group 'PlankDockTheme' in preferences file '/usr/share/plank/themes/Transparent/dock.theme' - using default value
[WARN 09:34:34.227125] [Preferences:378] Missing key 'HideTime' for group 'PlankDockTheme' in preferences file '/usr/share/plank/themes/Transparent/dock.theme' - using default value
[WARN 09:34:34.227151] [Preferences:378] Missing key 'GlowSize' for group 'PlankDockTheme' in preferences file '/usr/share/plank/themes/Transparent/dock.theme' - using default value
[WARN 09:34:34.227176] [Preferences:378] Missing key 'GlowTime' for group 'PlankDockTheme' in preferences file '/usr/share/plank/themes/Transparent/dock.theme' - using default value
[WARN 09:34:34.227200] [Preferences:378] Missing key 'GlowPulseTime' for group 'PlankDockTheme' in preferences file '/usr/share/plank/themes/Transparent/dock.theme' - using default value
[WARN 09:34:34.227225] [Preferences:378] Missing key 'UrgentHueShift' for group 'PlankDockTheme' in preferences file '/usr/share/plank/themes/Transparent/dock.theme' - using default value
[WARN 09:34:34.227248] [Preferences:378] Missing key 'ItemMoveTime' for group 'PlankDockTheme' in preferences file '/usr/share/plank/themes/Transparent/dock.theme' - using default value
[WARN 09:34:34.227273] [Preferences:378] Missing key 'CascadeHide' for group 'PlankDockTheme' in preferences file '/usr/share/plank/themes/Transparent/dock.theme' - using default value
[WARN 09:34:34.227298] [Preferences:378] Missing key 'BadgeColor' for group 'PlankDockTheme' in preferences file '/usr/share/plank/themes/Transparent/dock.theme' - using default value
[DEBUG 09:34:34.228250] [ItemFactory:176] Loading dock elements from '/home/carlo/.config/plank/dock1/launchers'
[DEBUG 09:34:34.240761] [Preferences:349] Loading preferences from file '/home/carlo/.config/plank/dock1/launchers/gnome-system-monitor.dockitem'
[DEBUG 09:34:34.241980] [Preferences:349] Loading preferences from file '/home/carlo/.config/plank/dock1/launchers/webapps.dockitem'
[DEBUG 09:34:34.243117] [Preferences:349] Loading preferences from file '/home/carlo/.config/plank/dock1/launchers/Software.dockitem'
[DEBUG 09:34:34.260227] [Preferences:349] Loading preferences from file '/home/carlo/.config/plank/dock1/launchers/org.kde.dolphin.dockitem'
[DEBUG 09:34:34.265607] [Preferences:349] Loading preferences from file '/home/carlo/.config/plank/dock1/launchers/waterfox.dockitem'
[DEBUG 09:34:34.268506] [Preferences:349] Loading preferences from file '/home/carlo/.config/plank/dock1/launchers/google-earth-pro.dockitem'
[DEBUG 09:34:34.271307] [Preferences:349] Loading preferences from file '/home/carlo/.config/plank/dock1/launchers/qalculate-gtk.dockitem'
[DEBUG 09:34:34.283371] [Preferences:349] Loading preferences from file '/home/carlo/.config/plank/dock1/launchers/cpumonitor.dockitem'
[WARN 09:34:34.302309] [Preferences:192] '/home/carlo/.config/plank/dock1/launchers/onboard.dockitem' is read-only!
[DEBUG 09:34:34.302474] [Preferences:349] Loading preferences from file '/home/carlo/.config/plank/dock1/launchers/onboard.dockitem'
[DEBUG 09:34:34.309415] [Preferences:349] Loading preferences from file '/home/carlo/.config/plank/dock1/launchers/clock.dockitem'
[DEBUG 09:34:34.320424] [Preferences:349] Loading preferences from file '/home/carlo/.config/plank/dock1/launchers/palemoon.dockitem'
[DEBUG 09:34:34.329265] [Preferences:349] Loading preferences from file '/home/carlo/.config/plank/dock1/launchers/opera.dockitem'
[DEBUG 09:34:34.352143] [Preferences:349] Loading preferences from file '/home/carlo/.config/plank/dock1/launchers/xfce-settings-manager.dockitem'
[DEBUG 09:34:34.359315] [Preferences:349] Loading preferences from file '/home/carlo/.config/plank/dock1/launchers/minitube.dockitem'
[DEBUG 09:34:34.368441] [Preferences:349] Loading preferences from file '/home/carlo/.config/plank/dock1/launchers/xfce4-terminal.dockitem'
[DEBUG 09:34:34.467932] [Unity:164] Initializing LauncherEntry support
[INFO 09:34:34.468241] [HideManager:616] Barriers enabled (XInput 2.3 support)
[DEBUG 09:34:34.468311] [PositionManager:675] Without draw_values there is trouble ahead
[DEBUG 09:34:34.476609] [Unity:133] com.canonical.Unity acquired
[WARN 09:34:34.590361] Creating surface took WAY TOO LONG (111ms), enabled downscaling for this cache!
[WARN 09:34:34.769835] Creating surface took WAY TOO LONG (33ms), enabled downscaling for this cache!
[INFO 09:34:34.819083] [DockRenderer:481] Cairo.SurfaceType: XLIB
[WARN 09:34:37.838996] Creating surface took WAY TOO LONG (35ms), enabled downscaling for this cache!
[DEBUG 09:34:46.788106] [GLib] posix_spawn avoided (automatic reaping requested) (fd close requested)