diff --git a/wayvr/src/assets/gui/keyboard.xml b/wayvr/src/assets/gui/keyboard.xml
index 6378a1b..be35e18 100644
--- a/wayvr/src/assets/gui/keyboard.xml
+++ b/wayvr/src/assets/gui/keyboard.xml
@@ -141,7 +141,7 @@
 
   <template name="Panel">
     <Button macro="button_style" id="overlay_${idx}" tooltip_str="${name}" _context_name="${name}" _press="::ContextMenuOpen menu_panel">
-      <sprite width="38" height="38" color="~color_text" src_builtin="edit/panel.svg" />
+      <sprite width="38" height="38" color="~color_text" src="${icon}" />
     </Button>
   </template>
 
diff --git a/wayvr/src/gui/panel/mod.rs b/wayvr/src/gui/panel/mod.rs
index 519294b..88fe379 100644
--- a/wayvr/src/gui/panel/mod.rs
+++ b/wayvr/src/gui/panel/mod.rs
@@ -1,8 +1,9 @@
-use std::{cell::RefCell, rc::Rc};
+use std::{cell::RefCell, collections::HashMap, rc::Rc};
 
 use anyhow::Context;
 use button::setup_custom_button;
 use glam::{Affine2, Vec2, vec2};
+use idmap::IdMap;
 use label::setup_custom_label;
 use wgui::{
     assets::AssetPath,
@@ -67,6 +68,7 @@ pub struct GuiPanel<S> {
     pub on_notify: Option<OnNotifyFunc<S>>,
     pub initialized: bool,
     pub doc_extra: Option<ParseDocumentExtra>,
+    pub extra_attribs: IdMap<BackendAttrib, BackendAttribValue>,
     interaction_transform: Option<Affine2>,
     context: WguiContext,
     timestep: Timestep,
@@ -182,6 +184,7 @@ impl<S: 'static> GuiPanel<S> {
             last_content_size: Vec2::ZERO,
             doc_extra: Some(doc_params.extra),
             custom_elems,
+            extra_attribs: Default::default(),
             context_menu: Default::default(),
             on_custom_attrib: params.on_custom_attrib,
             on_custom_attrib_inner,
@@ -443,8 +446,8 @@ impl<S: 'static> OverlayBackend for GuiPanel<S> {
     fn get_interaction_transform(&mut self) -> Option<Affine2> {
         self.interaction_transform
     }
-    fn get_attrib(&self, _attrib: BackendAttrib) -> Option<BackendAttribValue> {
-        None
+    fn get_attrib(&self, attrib: BackendAttrib) -> Option<BackendAttribValue> {
+        self.extra_attribs.get(&attrib).cloned()
     }
     fn set_attrib(&mut self, _app: &mut AppState, _value: BackendAttribValue) -> bool {
         false
diff --git a/wayvr/src/gui/panel/overlay_list.rs b/wayvr/src/gui/panel/overlay_list.rs
index caa08ce..bf8ea98 100644
--- a/wayvr/src/gui/panel/overlay_list.rs
+++ b/wayvr/src/gui/panel/overlay_list.rs
@@ -14,7 +14,7 @@ use crate::windowing::{OverlayID, backend::OverlayEventData, window::OverlayCate
 /// Helper for managing a list of overlays
 /// Populates `id="panels_root"` with `<Screen>`, `<Mirror>`, `<Panel>` templates
 /// Populates `id="apps_root"` with `<App>` templates (optional)
-/// Uses the following parameters: `name` (All), `display` (Screen, Mirror), `icon` (App)
+/// Uses the following parameters: `name` (All), `display` (Screen, Mirror), `icon` (App, Panel)
 pub struct OverlayList {
     overlay_buttons: SecondaryMap<OverlayID, Rc<ComponentButton>>,
 }
@@ -63,7 +63,16 @@ impl OverlayList {
                             );
                             ("Mirror", panels_root)
                         }
-                        OverlayCategory::Panel => ("Panel", panels_root),
+                        OverlayCategory::Panel => {
+                            let icon: Rc<str> = if let Some(icon) = meta.icon.as_ref() {
+                                icon.to_string().into()
+                            } else {
+                                "edit/panel.svg".into()
+                            };
+
+                            params.insert("icon".into(), icon);
+                            ("Panel", panels_root)
+                        }
                         OverlayCategory::WayVR => {
                             params.insert(
                                 "icon".into(),
diff --git a/wayvr/src/overlays/custom.rs b/wayvr/src/overlays/custom.rs
index 986fa9f..ee43ce9 100644
--- a/wayvr/src/overlays/custom.rs
+++ b/wayvr/src/overlays/custom.rs
@@ -1,7 +1,14 @@
-use std::{sync::Arc, time::Duration};
+use std::{
+    sync::{Arc, LazyLock},
+    time::Duration,
+};
 
 use glam::{Affine3A, Quat, Vec3, vec3};
-use wlx_common::windowing::OverlayWindowState;
+use regex::Regex;
+use wlx_common::{
+    overlays::{BackendAttrib, BackendAttribValue},
+    windowing::OverlayWindowState,
+};
 
 use crate::{
     gui::{
@@ -15,7 +22,22 @@ use crate::{
     },
 };
 
-struct CustomPanelState {}
+static ENV_VAR_REGEX: LazyLock<Regex> = LazyLock::new(|| {
+    Regex::new(r"\$\{([A-Z_][A-Z0-9_]*)}|\$([A-Z_][A-Z0-9_]*)").unwrap() // want panic
+});
+
+pub(super) fn expand_env_vars(template: &str) -> String {
+    ENV_VAR_REGEX
+        .replace_all(template, |caps: &regex::Captures| {
+            let var_name = caps.get(1).or_else(|| caps.get(2)).unwrap().as_str();
+            std::env::var(var_name)
+                .inspect_err(|e| log::warn!("Unable to substitute env var {var_name}: {e:?}"))
+                .unwrap_or_default()
+        })
+        .into_owned()
+}
+
+struct CustomPanelState;
 
 pub fn create_custom(app: &mut AppState, name: Arc<str>) -> Option<OverlayWindowConfig> {
     let params = NewGuiPanelParams {
@@ -24,10 +46,17 @@ pub fn create_custom(app: &mut AppState, name: Arc<str>) -> Option<OverlayWindow
     };
 
     let mut panel =
-        GuiPanel::new_from_template(app, &format!("gui/{name}.xml"), CustomPanelState {}, params)
+        GuiPanel::new_from_template(app, &format!("gui/{name}.xml"), CustomPanelState, params)
             .inspect_err(|e| log::warn!("Error creating '{name}': {e:?}"))
             .ok()?;
 
+    if let Some(icon) = panel.parser_state.data.var_map.get("_panel_icon") {
+        let icon = expand_env_vars(&icon);
+        panel
+            .extra_attribs
+            .insert(BackendAttrib::Icon, BackendAttribValue::Icon(icon.into()));
+    }
+
     panel
         .update_layout(app)
         .inspect_err(|e| log::warn!("Error layouting '{name}': {e:?}"))
diff --git a/wlx-common/src/overlays.rs b/wlx-common/src/overlays.rs
index 633d2be..4544648 100644
--- a/wlx-common/src/overlays.rs
+++ b/wlx-common/src/overlays.rs
@@ -19,7 +19,7 @@ pub enum ToastDisplayMethod {
 	Watch,
 }
 
-#[derive(Clone, Copy)]
+#[derive(Debug, Clone, Copy, IntegerId, PartialEq)]
 pub enum BackendAttrib {
 	Stereo,
 	MouseTransform,