diff --git a/packages/x-date-pickers-pro/src/DateRangePicker/DateRangePickerToolbar.tsx b/packages/x-date-pickers-pro/src/DateRangePicker/DateRangePickerToolbar.tsx
index 1380e8e2a975..77ba0bcbaafd 100644
--- a/packages/x-date-pickers-pro/src/DateRangePicker/DateRangePickerToolbar.tsx
+++ b/packages/x-date-pickers-pro/src/DateRangePicker/DateRangePickerToolbar.tsx
@@ -7,7 +7,6 @@ import { unstable_composeClasses as composeClasses } from '@mui/utils';
 import {
   PickersToolbar,
   PickersToolbarButton,
-  pickersToolbarClasses,
   useUtils,
   BaseToolbarProps,
   useLocaleText,
@@ -47,12 +46,7 @@ const DateRangePickerToolbarRoot = styled(PickersToolbar, {
   overridesResolver: (_, styles) => styles.root,
 })<{
   ownerState: DateRangePickerToolbarProps<any>;
-}>({
-  [`& .${pickersToolbarClasses.penIconButton}`]: {
-    position: 'relative',
-    top: 4,
-  },
-});
+}>({});
 
 const DateRangePickerToolbarContainer = styled('div', {
   name: 'MuiDateRangePickerToolbar',
diff --git a/packages/x-date-pickers-pro/src/DateRangePickerDay/DateRangePickerDay.tsx b/packages/x-date-pickers-pro/src/DateRangePickerDay/DateRangePickerDay.tsx
index b5618737f06f..cf7ba5a450a2 100644
--- a/packages/x-date-pickers-pro/src/DateRangePickerDay/DateRangePickerDay.tsx
+++ b/packages/x-date-pickers-pro/src/DateRangePickerDay/DateRangePickerDay.tsx
@@ -5,7 +5,7 @@ import { useLicenseVerifier } from '@mui/x-license-pro';
 import { alpha, styled, useThemeProps } from '@mui/material/styles';
 import { unstable_composeClasses as composeClasses } from '@mui/utils';
 import { useUtils } from '@mui/x-date-pickers/internals';
-import { PickersDay, pickersDayClasses, PickersDayProps } from '@mui/x-date-pickers/PickersDay';
+import { PickersDay, PickersDayProps } from '@mui/x-date-pickers/PickersDay';
 import {
   DateRangePickerDayClasses,
   getDateRangePickerDayUtilityClass,
@@ -253,13 +253,6 @@ const DateRangePickerDayDay = styled(PickersDay, {
   '& > *': {
     transform: 'scale(0.9)',
   },
-  ...(!ownerState.selected &&
-    ownerState.isHighlighting && {
-      opacity: 0.7,
-      [`&.${pickersDayClasses.dayOutsideMonth}`]: {
-        opacity: 0.4,
-      },
-    }),
   ...(ownerState.draggable && {
     cursor: 'grab',
   }),
diff --git a/packages/x-date-pickers/src/DateTimePicker/DateTimePickerToolbar.tsx b/packages/x-date-pickers/src/DateTimePicker/DateTimePickerToolbar.tsx
index 83bfd879d007..a664cc73845b 100644
--- a/packages/x-date-pickers/src/DateTimePicker/DateTimePickerToolbar.tsx
+++ b/packages/x-date-pickers/src/DateTimePicker/DateTimePickerToolbar.tsx
@@ -4,7 +4,6 @@ import { styled, useThemeProps, useTheme, Theme } from '@mui/material/styles';
 import { unstable_composeClasses as composeClasses } from '@mui/utils';
 import { PickersToolbarText } from '../internals/components/PickersToolbarText';
 import { PickersToolbar } from '../internals/components/PickersToolbar';
-import { pickersToolbarClasses } from '../internals/components/pickersToolbarClasses';
 import { PickersToolbarButton } from '../internals/components/PickersToolbarButton';
 import { useLocaleText, useUtils } from '../internals/hooks/useUtils';
 import { BaseToolbarProps, ExportedBaseToolbarProps } from '../internals/models/props/toolbar';
@@ -64,11 +63,6 @@ const DateTimePickerToolbarRoot = styled(PickersToolbar, {
       : undefined,
   justifyContent: 'space-around',
   position: 'relative',
-  [`& .${pickersToolbarClasses.penIconButton}`]: {
-    position: 'absolute',
-    top: 8,
-    ...(theme.direction === 'rtl' ? { left: 8 } : { right: 8 }),
-  },
 }));
 
 DateTimePickerToolbarRoot.propTypes = {
diff --git a/packages/x-date-pickers/src/PickersDay/PickersDay.tsx b/packages/x-date-pickers/src/PickersDay/PickersDay.tsx
index 1b5000c5fece..2e38a37992ae 100644
--- a/packages/x-date-pickers/src/PickersDay/PickersDay.tsx
+++ b/packages/x-date-pickers/src/PickersDay/PickersDay.tsx
@@ -109,15 +109,16 @@ const useUtilityClasses = (ownerState: PickersDayProps<any>) => {
     classes,
   } = ownerState;
 
+  const isHiddenDaySpacingFiller = outsideCurrentMonth && !showDaysOutsideCurrentMonth;
   const slots = {
     root: [
       'root',
-      selected && 'selected',
+      selected && !isHiddenDaySpacingFiller && 'selected',
       disabled && 'disabled',
       !disableMargin && 'dayWithMargin',
       !disableHighlightToday && today && 'today',
       outsideCurrentMonth && showDaysOutsideCurrentMonth && 'dayOutsideMonth',
-      outsideCurrentMonth && !showDaysOutsideCurrentMonth && 'hiddenDaySpacingFiller',
+      isHiddenDaySpacingFiller && 'hiddenDaySpacingFiller',
     ],
     hiddenDaySpacingFiller: ['hiddenDaySpacingFiller'],
   };
diff --git a/packages/x-date-pickers/src/TimePicker/TimePickerToolbar.tsx b/packages/x-date-pickers/src/TimePicker/TimePickerToolbar.tsx
index 0c1bc44bbfa1..61e9eafa0bf5 100644
--- a/packages/x-date-pickers/src/TimePicker/TimePickerToolbar.tsx
+++ b/packages/x-date-pickers/src/TimePicker/TimePickerToolbar.tsx
@@ -5,7 +5,6 @@ import { unstable_composeClasses as composeClasses } from '@mui/utils';
 import { PickersToolbarText } from '../internals/components/PickersToolbarText';
 import { PickersToolbarButton } from '../internals/components/PickersToolbarButton';
 import { PickersToolbar } from '../internals/components/PickersToolbar';
-import { pickersToolbarClasses } from '../internals/components/pickersToolbarClasses';
 import { arrayIncludes } from '../internals/utils/utils';
 import { useLocaleText, useUtils } from '../internals/hooks/useUtils';
 import { useMeridiemMode } from '../internals/hooks/date-helpers-hooks';
@@ -53,11 +52,7 @@ const TimePickerToolbarRoot = styled(PickersToolbar, {
   overridesResolver: (props, styles) => styles.root,
 })<{
   ownerState: TimePickerToolbarProps<any>;
-}>({
-  [`& .${pickersToolbarClasses.penIconButtonLandscape}`]: {
-    marginTop: 'auto',
-  },
-});
+}>({});
 
 const TimePickerToolbarSeparator = styled(PickersToolbarText, {
   name: 'MuiTimePickerToolbar',
diff --git a/packages/x-date-pickers/src/internals/components/pickersToolbarClasses.ts b/packages/x-date-pickers/src/internals/components/pickersToolbarClasses.ts
index f244e40cba97..09ecae7d30ce 100644
--- a/packages/x-date-pickers/src/internals/components/pickersToolbarClasses.ts
+++ b/packages/x-date-pickers/src/internals/components/pickersToolbarClasses.ts
@@ -8,10 +8,6 @@ export interface PickersToolbarClasses {
   root: string;
   /** Styles applied to the content element. */
   content: string;
-  /** Styles applied to the pen icon button element. */
-  penIconButton: string;
-  /** Styles applied to the pen icon button element in landscape mode. */
-  penIconButtonLandscape: string;
 }
 
 export type PickersToolbarClassKey = keyof PickersToolbarClasses;
@@ -23,6 +19,4 @@ export function getPickersToolbarUtilityClass(slot: string) {
 export const pickersToolbarClasses = generateUtilityClasses('MuiPickersToolbar', [
   'root',
   'content',
-  'penIconButton',
-  'penIconButtonLandscape',
 ]);
diff --git a/packages/x-date-pickers/src/themeAugmentation/themeAugmentation.spec.ts b/packages/x-date-pickers/src/themeAugmentation/themeAugmentation.spec.ts
index 6f32a6967c7f..3fe257299475 100644
--- a/packages/x-date-pickers/src/themeAugmentation/themeAugmentation.spec.ts
+++ b/packages/x-date-pickers/src/themeAugmentation/themeAugmentation.spec.ts
@@ -14,11 +14,7 @@ import {
 } from '../TimeClock';
 import { datePickerToolbarClasses } from '../DatePicker';
 import { dateTimePickerToolbarClasses } from '../DateTimePicker';
-import {
-  pickersArrowSwitcherClasses,
-  pickersPopperClasses,
-  pickersToolbarClasses,
-} from '../internals';
+import { pickersArrowSwitcherClasses, pickersPopperClasses } from '../internals';
 import { pickersDayClasses } from '../PickersDay';
 import { timePickerToolbarClasses } from '../TimePicker';
 import { pickersMonthClasses } from '../MonthCalendar';
@@ -410,9 +406,6 @@ createTheme({
       styleOverrides: {
         root: {
           backgroundColor: 'red',
-          [`.${pickersToolbarClasses.penIconButton}`]: {
-            backgroundColor: 'green',
-          },
         },
         // @ts-expect-error invalid MuiPickersToolbar class key
         contentWrapper: {