layout: Reset unfullscreen view offset when removing window

Another old bug found by randomized tests after I expanded the testing mock
window.

src/layout/scrolling.rs

@@ -1063,6 +1063,13 @@ impl<W: LayoutElement> ScrollingSpace<W> {
         let tile = column.tiles.remove(tile_idx);
         column.data.remove(tile_idx);
 
+        // If we're removing a pending-unfullscreen window, we need to clear the stored view
+        // offset. There might be other pending-unfullscreen windows in this column but that's kind
+        // of an edge case, don't think we need to handle that.
+        if column_idx == self.active_column_idx && tile.is_fullscreen() && !column.is_fullscreen {
+            self.view_offset_before_fullscreen = None;
+        }
+
         // If one window is left, reset its weight to 1.
         if column.data.len() == 1 {
             if let WindowHeight::Auto { weight } = &mut column.data[0].height {

src/layout/tests.rs

@@ -3262,6 +3262,52 @@ fn windowed_fullscreen_to_fullscreen() {
     check_ops(&ops);
 }
 
+#[test]
+fn move_pending_unfullscreen_window_out_of_active_column() {
+    let ops = [
+        Op::AddOutput(1),
+        Op::AddWindow {
+            params: TestWindowParams::new(1),
+        },
+        Op::FullscreenWindow(1),
+        Op::Communicate(1),
+        Op::AddWindow {
+            params: TestWindowParams::new(2),
+        },
+        Op::ConsumeWindowIntoColumn,
+        // Window 1 is now pending unfullscreen.
+        // Moving it out should reset view_offset_before_fullscreen.
+        Op::MoveWindowToWorkspaceDown,
+    ];
+
+    check_ops(&ops);
+}
+
+#[test]
+fn move_unfocused_pending_unfullscreen_window_out_of_active_column() {
+    let ops = [
+        Op::AddOutput(1),
+        Op::AddWindow {
+            params: TestWindowParams::new(1),
+        },
+        Op::FullscreenWindow(1),
+        Op::Communicate(1),
+        Op::AddWindow {
+            params: TestWindowParams::new(2),
+        },
+        Op::ConsumeWindowIntoColumn,
+        // Window 1 is now pending unfullscreen.
+        // Moving it out should reset view_offset_before_fullscreen.
+        Op::FocusWindowDown,
+        Op::MoveWindowToWorkspace {
+            window_id: Some(1),
+            workspace_idx: 1,
+        },
+    ];
+
+    check_ops(&ops);
+}
+
 fn parent_id_causes_loop(layout: &Layout<TestWindow>, id: usize, mut parent_id: usize) -> bool {
     if parent_id == id {
         return true;