diff --git a/README.md b/README.md
index c71f728..0c4d31a 100644
--- a/README.md
+++ b/README.md
@@ -16,7 +16,7 @@ This package is source-only: consumers import directly from `src/` via the
 | `dashgui/tiles` | `src/tiles/` | `Tile`, `TILE_SIZE`, `tileBaseSx` |
 | `dashgui/ElevatedPill` | `src/ElevatedPill.jsx` | `ElevatedPill`, `ToggleElevatedPill`, `ActionElevatedPill` |
 | `dashgui/SingleLineTextEdit` | `src/SingleLineTextEdit.jsx` | Centralized single-line text field |
-| `dashgui/FillSpace` | `src/FillSpace.jsx` | `FillSpace` — viewport-height spacer between header/footer refs; optional repeating `measureElement` |
+| `dashgui/FillSpace` | `src/FillSpace.jsx` | `FillSpace` — paginates `items` via `renderItem`, filling the viewport space between `aboveRef`/`belowRef`; wheel flips pages |
 
 ## Design rules
 
diff --git a/src/FillSpace.jsx b/src/FillSpace.jsx
index 5891f6f..498e423 100644
--- a/src/FillSpace.jsx
+++ b/src/FillSpace.jsx
@@ -260,13 +260,14 @@ class FillSpace extends Component {
 
     // FillSpace owns current page, wheel-pagination and the pagination header.
     // Caller feeds `items` plus one row element via `renderItem` (component
-    // type or callback).
+    // type or callback). `items` may be undefined while data is loading.
     const { pageSize, currentPage, viewportHeight } = this.state;
-    const total = items.length;
+    const list = Array.isArray(items) ? items : [];
+    const total = list.length;
     const pageCount = Math.max(1, Math.ceil(total / Math.max(1, pageSize)));
     const safePage = Math.min(Math.max(1, currentPage), pageCount);
     const offset = (safePage - 1) * pageSize;
-    const pageItems = items.slice(offset, offset + pageSize);
+    const pageItems = list.slice(offset, offset + pageSize);
     const showPagination = total > pageSize;
     // Hidden data-free probe: measures `renderItem` itself (no data).
     const probe = renderProbeElement(renderItem);
diff --git a/src/dev/mock-pages/FillSpaceMockPage.jsx b/src/dev/mock-pages/FillSpaceMockPage.jsx
index caf8d16..4984765 100644
--- a/src/dev/mock-pages/FillSpaceMockPage.jsx
+++ b/src/dev/mock-pages/FillSpaceMockPage.jsx
@@ -1,14 +1,32 @@
 import { Component, createRef } from 'react';
 import Box from '@mui/material/Box';
+import ListItemButton from '@mui/material/ListItemButton';
+import ListItemText from '@mui/material/ListItemText';
 import Paper from '@mui/material/Paper';
 import Typography from '@mui/material/Typography';
 import FillSpace from '../../FillSpace';
 import { ComponentDocs } from '../ComponentDocs';
 
+/** Row renderer: component types are rendered as elements by FillSpace. */
+class Row extends Component {
+  render() {
+    const { item } = this.props;
+    return (
+      <ListItemButton divider disabled={!item}>
+        <ListItemText primary={item ? item.name : '\u00A0'} />
+      </ListItemButton>
+    );
+  }
+}
+
+const SAMPLE_ITEMS = Array.from({ length: 40 }, (_, i) => ({
+  id: i + 1,
+  name: `Eintrag ${i + 1}`,
+}));
+
 /**
- * Mock page exercising FillSpace: real content on top, and a repeating
- * `measureElement` filling only the leftover space down to the end of the
- * viewport.
+ * Mock page exercising FillSpace: header/footer refs, `items` + `renderItem`,
+ * wheel pagination and the built-in pagination header.
  */
 class FillSpaceMockPage extends Component {
   constructor(props) {
@@ -16,27 +34,26 @@ class FillSpaceMockPage extends Component {
     this.ex1 = { header: createRef(), footer: createRef() };
     this.ex2 = { header: createRef(), footer: createRef() };
     this.ex3 = { header: createRef(), footer: createRef() };
-    this.state = { fitCount: null };
   }
 
   render() {
-    const { fitCount } = this.state;
     return (
       <Box sx={{ display: 'flex', flexDirection: 'column', gap: 3 }}>
         <Typography variant="body2" color="text.secondary">
-          FillSpace renders real content on top and repeats the measurement
-          element until the end of the page.
+          FillSpace paginates <code>items</code> via a <code>renderItem</code>{' '}
+          row, measures the row height, fills the leftover viewport space and
+          flips pages on wheel scroll.
         </Typography>
 
-        {/* Main example: content + repeating fill to end of page */}
+        {/* Main example: items + renderItem to end of page */}
         <Paper variant="outlined" sx={{ p: 2 }}>
           <Typography variant="subtitle2" gutterBottom>
-            Content + repeating element to end of page
+            Items + renderItem, filled to end of page
           </Typography>
           <Box sx={{ display: 'flex', flexDirection: 'column' }}>
             <Box
               ref={this.ex1.header}
-              sx={{ bgcolor: '#e2e8f0', p: 1, borderRadius: 1 }}
+              sx={{ bgcolor: '#e2e8f0', p: 1, borderRadius: 1, mb: 1 }}
             >
               <Typography variant="caption">Header (measured)</Typography>
             </Box>
@@ -44,65 +61,17 @@ class FillSpaceMockPage extends Component {
             <FillSpace
               aboveRef={this.ex1.header}
               belowRef={this.ex1.footer}
-              measureElement={
-                <Box
-                  sx={{
-                    bgcolor: '#dbeafe',
-                    p: 2,
-                    borderRadius: 1,
-                    textAlign: 'center',
-                  }}
-                >
-                  <Typography variant="body2">Einheit</Typography>
-                </Box>
-              }
-              onMeasurement={(count) => this.setState({ fitCount: count })}
-            >
-              <Box
-                sx={{
-                  bgcolor: '#fef3c7',
-                  p: 2,
-                  borderRadius: 1,
-                }}
-              >
-                <Typography variant="body2" fontWeight={600}>
-                  Echte Inhalte (children)
-                </Typography>
-                <Typography variant="caption" color="text.secondary">
-                  Diese Zeilen stehen oben, darunter wiederholt sich die
-                  Einheit bis zum Seitenende.
-                </Typography>
-                <Box
-                  sx={{
-                    mt: 1,
-                    px: 1.5,
-                    py: 0.75,
-                    borderRadius: 1,
-                    bgcolor: 'background.paper',
-                    border: '1px dashed',
-                    borderColor: 'divider',
-                  }}
-                >
-                  <Typography variant="caption" component="span">
-                    📏 onMeasurement (würden ohne Inhalt passen):&nbsp;
-                  </Typography>
-                  <Typography
-                    variant="caption"
-                    component="span"
-                    fontWeight={700}
-                    color="primary"
-                  >
-                    {fitCount != null ? `${fitCount} Einheiten` : '…'}
-                  </Typography>
-                </Box>
-              </Box>
-            </FillSpace>
+              items={SAMPLE_ITEMS}
+              renderItem={Row}
+              reserveBottom={32}
+              minPageSize={5}
+            />
 
             <Box
               ref={this.ex1.footer}
-              sx={{ bgcolor: '#e2e8f0', p: 1, borderRadius: 1 }}
+              sx={{ bgcolor: '#e2e8f0', p: 1, borderRadius: 1, mt: 1 }}
             >
-              <Typography variant="caption">Footer (measured)</Typography>
+              <Typography variant="caption">Footer (reserved)</Typography>
             </Box>
           </Box>
         </Paper>
@@ -115,7 +84,7 @@ class FillSpaceMockPage extends Component {
           <Box sx={{ display: 'flex', flexDirection: 'column' }}>
             <Box
               ref={this.ex2.header}
-              sx={{ bgcolor: '#e2e8f0', p: 1, borderRadius: 1 }}
+              sx={{ bgcolor: '#e2e8f0', p: 1, borderRadius: 1, mb: 1 }}
             >
               <Typography variant="caption">Header</Typography>
             </Box>
@@ -123,24 +92,15 @@ class FillSpaceMockPage extends Component {
             <FillSpace
               aboveRef={this.ex2.header}
               belowRef={this.ex2.footer}
+              items={SAMPLE_ITEMS.slice(0, 6)}
+              renderItem={Row}
+              minPageSize={4}
               minHeight={200}
-            >
-              <Box
-                sx={{
-                  bgcolor: '#fef3c7',
-                  p: 2,
-                  borderRadius: 1,
-                }}
-              >
-                <Typography variant="body2">
-                  Minimum height of 200px enforced.
-                </Typography>
-              </Box>
-            </FillSpace>
+            />
 
             <Box
               ref={this.ex2.footer}
-              sx={{ bgcolor: '#e2e8f0', p: 1, borderRadius: 1 }}
+              sx={{ bgcolor: '#e2e8f0', p: 1, borderRadius: 1, mt: 1 }}
             >
               <Typography variant="caption">Footer</Typography>
             </Box>
@@ -155,7 +115,7 @@ class FillSpaceMockPage extends Component {
           <Box sx={{ display: 'flex', flexDirection: 'column' }}>
             <Box
               ref={this.ex3.header}
-              sx={{ bgcolor: '#e2e8f0', p: 1, borderRadius: 1 }}
+              sx={{ bgcolor: '#e2e8f0', p: 1, borderRadius: 1, mb: 1 }}
             >
               <Typography variant="caption">Header</Typography>
             </Box>
@@ -163,25 +123,15 @@ class FillSpaceMockPage extends Component {
             <FillSpace
               aboveRef={this.ex3.header}
               belowRef={this.ex3.footer}
+              items={SAMPLE_ITEMS}
+              renderItem={Row}
+              minPageSize={5}
               debug
-            >
-              <Box
-                sx={{
-                  bgcolor: '#dcfce7',
-                  p: 2,
-                  borderRadius: 1,
-                }}
-              >
-                <Typography variant="body2">
-                  Green background shows actual spacer bounds; purple overlay
-                  shows full viewport coverage.
-                </Typography>
-              </Box>
-            </FillSpace>
+            />
 
             <Box
               ref={this.ex3.footer}
-              sx={{ bgcolor: '#e2e8f0', p: 1, borderRadius: 1 }}
+              sx={{ bgcolor: '#e2e8f0', p: 1, borderRadius: 1, mt: 1 }}
             >
               <Typography variant="caption">Footer</Typography>
             </Box>
diff --git a/src/dev/screenshots/ScreenshotHarness.jsx b/src/dev/screenshots/ScreenshotHarness.jsx
index 4636e0a..4fc7ed5 100644
--- a/src/dev/screenshots/ScreenshotHarness.jsx
+++ b/src/dev/screenshots/ScreenshotHarness.jsx
@@ -2,6 +2,8 @@ import { Component, createRef } from 'react';
 import Alert from '@mui/material/Alert';
 import Box from '@mui/material/Box';
 import Chip from '@mui/material/Chip';
+import ListItemButton from '@mui/material/ListItemButton';
+import ListItemText from '@mui/material/ListItemText';
 import Typography from '@mui/material/Typography';
 import AddIcon from '@mui/icons-material/Add';
 import FolderIcon from '@mui/icons-material/FolderOutlined';
@@ -307,8 +309,8 @@ class ScreenshotHarness extends Component {
 }
 
 /**
- * Deterministic FillSpace example for the screenshot harness. Bound with a
- * `maxHeight` so the reference is stable regardless of the viewport height.
+ * Deterministic FillSpace example for the screenshot harness:
+ * `items` + a component `renderItem`, bounded by above/below refs.
  */
 class FillSpaceExample extends Component {
   constructor(props) {
@@ -322,7 +324,7 @@ class FillSpaceExample extends Component {
       <Box sx={{ display: 'flex', flexDirection: 'column' }}>
         <Box
           ref={this.headerRef}
-          sx={{ bgcolor: '#e2e8f0', p: 1, borderRadius: 1 }}
+          sx={{ bgcolor: '#e2e8f0', p: 1, borderRadius: 1, mb: 1 }}
         >
           <Typography variant="caption">Header (gemessen)</Typography>
         </Box>
@@ -330,26 +332,15 @@ class FillSpaceExample extends Component {
         <FillSpace
           aboveRef={this.headerRef}
           belowRef={this.footerRef}
+          items={FILL_SAMPLE_ITEMS}
+          renderItem={FillRow}
+          minPageSize={4}
           minHeight={80}
-          maxHeight={220}
-        >
-          <Box
-            sx={{
-              bgcolor: '#dbeafe',
-              p: 2,
-              borderRadius: 1,
-              height: '100%',
-            }}
-          >
-            <Typography variant="body2">
-              FillSpace füllt den Platz zwischen Header und Footer.
-            </Typography>
-          </Box>
-        </FillSpace>
+        />
 
         <Box
           ref={this.footerRef}
-          sx={{ bgcolor: '#e2e8f0', p: 1, borderRadius: 1 }}
+          sx={{ bgcolor: '#e2e8f0', p: 1, borderRadius: 1, mt: 1 }}
         >
           <Typography variant="caption">Footer (gemessen)</Typography>
         </Box>
@@ -358,9 +349,36 @@ class FillSpaceExample extends Component {
   }
 }
 
+/** Row renderer used by the FillSpace harness examples. */
+class FillRow extends Component {
+  render() {
+    const { item } = this.props;
+    return (
+      <ListItemButton divider disabled={!item}>
+        <ListItemText
+          primary={
+            item ? (
+              `${item.name}`
+            ) : (
+              <Typography variant="body2" sx={{ visibility: 'hidden' }}>
+                Platzhalter
+              </Typography>
+            )
+          }
+        />
+      </ListItemButton>
+    );
+  }
+}
+
+const FILL_SAMPLE_ITEMS = Array.from({ length: 24 }, (_, i) => ({
+  id: i + 1,
+  name: `Eintrag ${i + 1}`,
+}));
+
 /**
- * FillSpace with a repeating measurement element plus real children on top,
- * for the screenshot harness. Bound with maxHeight so the reference is stable.
+ * FillSpace with `items` + a component `renderItem`, for the screenshot
+ * harness. Bounded by above/below refs so the reference is stable.
  */
 class FillSpaceMeasureExample extends Component {
   constructor(props) {
@@ -374,7 +392,7 @@ class FillSpaceMeasureExample extends Component {
       <Box sx={{ display: 'flex', flexDirection: 'column' }}>
         <Box
           ref={this.headerRef}
-          sx={{ bgcolor: '#e2e8f0', p: 1, borderRadius: 1 }}
+          sx={{ bgcolor: '#e2e8f0', p: 1, borderRadius: 1, mb: 1 }}
         >
           <Typography variant="caption">Header</Typography>
         </Box>
@@ -382,36 +400,15 @@ class FillSpaceMeasureExample extends Component {
         <FillSpace
           aboveRef={this.headerRef}
           belowRef={this.footerRef}
-          measureElement={
-            <Box
-              sx={{
-                bgcolor: '#c7d2fe',
-                p: 1,
-                borderRadius: 1,
-                textAlign: 'center',
-              }}
-            >
-              <Typography variant="caption">Einheit</Typography>
-            </Box>
-          }
-          measureGap={8}
+          items={FILL_SAMPLE_ITEMS}
+          renderItem={FillRow}
+          minPageSize={4}
           minHeight={60}
-          maxHeight={260}
-        >
-          <Box
-            sx={{
-              bgcolor: '#fef3c7',
-              p: 1,
-              borderRadius: 1,
-            }}
-          >
-            <Typography variant="body2">Echte Inhalte</Typography>
-          </Box>
-        </FillSpace>
+        />
 
         <Box
           ref={this.footerRef}
-          sx={{ bgcolor: '#e2e8f0', p: 1, borderRadius: 1 }}
+          sx={{ bgcolor: '#e2e8f0', p: 1, borderRadius: 1, mt: 1 }}
         >
           <Typography variant="caption">Footer</Typography>
         </Box>