diff --git a/crates/egui/src/containers/panel.rs b/crates/egui/src/containers/panel.rs
index 1b8e9f320..a5f57f5db 100644
--- a/crates/egui/src/containers/panel.rs
+++ b/crates/egui/src/containers/panel.rs
@@ -859,8 +859,27 @@ impl Panel {
 
     /// The configured [`Frame`], or the default side/top panel frame for this [`Ui`].
     fn resolve_frame(&self, ui: &Ui) -> Frame {
-        self.frame
-            .unwrap_or_else(|| Frame::side_top_panel(ui.style()))
+        let mut frame = self
+            .frame
+            .unwrap_or_else(|| Frame::side_top_panel(ui.style()));
+
+        let has_separator_line = self.show_separator_line || self.resizable;
+
+        if has_separator_line {
+            // The separator line has a thickness that we need to account for.
+            let widgets = &ui.style().visuals.widgets;
+            let stroke_width = widgets.noninteractive.bg_stroke.width.round() as i8;
+
+            let margin_side = match self.side {
+                PanelSide::Left => &mut frame.inner_margin.right,
+                PanelSide::Right => &mut frame.inner_margin.left,
+                PanelSide::Top => &mut frame.inner_margin.bottom,
+                PanelSide::Bottom => &mut frame.inner_margin.top,
+            };
+            *margin_side = (*margin_side).saturating_add(stroke_width);
+        }
+
+        frame
     }
 
     /// Panel is fully closed. If the user is still dragging the resize handle
diff --git a/crates/egui_demo_app/tests/snapshots/clock.png b/crates/egui_demo_app/tests/snapshots/clock.png
index 347bdd568..87c4b5374 100644
--- a/crates/egui_demo_app/tests/snapshots/clock.png
+++ b/crates/egui_demo_app/tests/snapshots/clock.png
@@ -1,3 +1,3 @@
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-oid sha256:288e11a1fa684575155826a760d5aecc5855e1f4b68bc8954441bf3ac015ee84
-size 335175
+oid sha256:dda3ad81551d0001bb9d3614a266010e44c8c18700964d8734c3e825672d9383
+size 334759
diff --git a/crates/egui_demo_app/tests/snapshots/custom3d.png b/crates/egui_demo_app/tests/snapshots/custom3d.png
index 6778d8b92..fc393aa9e 100644
--- a/crates/egui_demo_app/tests/snapshots/custom3d.png
+++ b/crates/egui_demo_app/tests/snapshots/custom3d.png
@@ -1,3 +1,3 @@
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-size 92770
+oid sha256:9035687ecd3aae0d8639000f091592d69acec0e73e7ba17e04c9794c5321cb1e
+size 92771
diff --git a/crates/egui_demo_app/tests/snapshots/easymarkeditor.png b/crates/egui_demo_app/tests/snapshots/easymarkeditor.png
index 81485c09a..7f908cbea 100644
--- a/crates/egui_demo_app/tests/snapshots/easymarkeditor.png
+++ b/crates/egui_demo_app/tests/snapshots/easymarkeditor.png
@@ -1,3 +1,3 @@
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diff --git a/crates/egui_demo_app/tests/snapshots/imageviewer.png b/crates/egui_demo_app/tests/snapshots/imageviewer.png
index 80725c619..7381f2737 100644
--- a/crates/egui_demo_app/tests/snapshots/imageviewer.png
+++ b/crates/egui_demo_app/tests/snapshots/imageviewer.png
@@ -1,3 +1,3 @@
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-oid sha256:1cf4c34af7b69cd8220b11ff7e355ddf8d7b52a43a60a1748abf9cc1d5c7da9b
-size 98869
+oid sha256:8d278d0d879e8cb44c4c2e65bdee4441616abcf3507adc37959ccf042991b31c
+size 98780
diff --git a/crates/egui_demo_lib/tests/snapshots/demos/Panels.png b/crates/egui_demo_lib/tests/snapshots/demos/Panels.png
index 14fa4884e..7e6beeac1 100644
--- a/crates/egui_demo_lib/tests/snapshots/demos/Panels.png
+++ b/crates/egui_demo_lib/tests/snapshots/demos/Panels.png
@@ -1,3 +1,3 @@
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-oid sha256:8d48079f85e9529f4b463bbaf2c948a64126388ef32df0584b586dc0ae48a35b
-size 344919
+oid sha256:d20f4bf882ee16abde6268fe766ceb67dccdfc5d2a509a952cef1d7af72dc3c6
+size 344141
diff --git a/crates/egui_demo_lib/tests/snapshots/demos/Tooltips.png b/crates/egui_demo_lib/tests/snapshots/demos/Tooltips.png
index a3fe390e6..0fdb9277d 100644
--- a/crates/egui_demo_lib/tests/snapshots/demos/Tooltips.png
+++ b/crates/egui_demo_lib/tests/snapshots/demos/Tooltips.png
@@ -1,3 +1,3 @@
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+oid sha256:125d6fe0cdc81a0c7973317e62c528c1beff7ceaedb9cb1fb91bc8d6674c8dc6
 size 62830
diff --git a/tests/egui_tests/tests/snapshots/panel_drag/between_collapsed.png b/tests/egui_tests/tests/snapshots/panel_drag/between_collapsed.png
index cb3b393e6..6c824bd91 100644
--- a/tests/egui_tests/tests/snapshots/panel_drag/between_collapsed.png
+++ b/tests/egui_tests/tests/snapshots/panel_drag/between_collapsed.png
@@ -1,3 +1,3 @@
 version https://git-lfs.github.com/spec/v1
-oid sha256:eba6e690937fbbd22c8edfce14078f50998e968324d8073d5db5829493d957e0
+oid sha256:9a21708315ae4514c1ff2c71075ccce2bef4627720808e4eebc9d7922388a17f
 size 5292
diff --git a/tests/egui_tests/tests/snapshots/panel_drag/between_initial_expanded.png b/tests/egui_tests/tests/snapshots/panel_drag/between_initial_expanded.png
index 06679d16d..6310e8309 100644
--- a/tests/egui_tests/tests/snapshots/panel_drag/between_initial_expanded.png
+++ b/tests/egui_tests/tests/snapshots/panel_drag/between_initial_expanded.png
@@ -1,3 +1,3 @@
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+oid sha256:a0c8d12d6f3741d33b993b5390fba5b845778a1f4dcf6d661513e65243978e18
 size 65797
diff --git a/tests/egui_tests/tests/snapshots/panel_drag/between_reopened.png b/tests/egui_tests/tests/snapshots/panel_drag/between_reopened.png
index 06679d16d..6310e8309 100644
--- a/tests/egui_tests/tests/snapshots/panel_drag/between_reopened.png
+++ b/tests/egui_tests/tests/snapshots/panel_drag/between_reopened.png
@@ -1,3 +1,3 @@
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 size 65797
diff --git a/tests/egui_tests/tests/snapshots/panel_drag/inside_initial.png b/tests/egui_tests/tests/snapshots/panel_drag/inside_initial.png
index 8a9963284..b25aa5581 100644
--- a/tests/egui_tests/tests/snapshots/panel_drag/inside_initial.png
+++ b/tests/egui_tests/tests/snapshots/panel_drag/inside_initial.png
@@ -1,3 +1,3 @@
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+oid sha256:054c9005865ff2d6c1ee6c76539453fbad6005d1c62693de5653c4bb00164322
+size 4881