diff --git a/theatre/package.json b/theatre/package.json
index 4deaade..aada9e9 100644
--- a/theatre/package.json
+++ b/theatre/package.json
@@ -74,6 +74,7 @@
     "react-error-boundary": "^3.1.3",
     "react-icons": "^4.2.0",
     "react-is": "^17.0.2",
+    "react-merge-refs": "^1.1.0",
     "react-shadow": "^19.0.2",
     "react-use": "^17.2.4",
     "react-use-gesture": "^9.1.3",
diff --git a/theatre/studio/src/panels/SequenceEditorPanel/DopeSheet/Right/LengthIndicator/LengthEditorPopover.tsx b/theatre/studio/src/panels/SequenceEditorPanel/DopeSheet/Right/LengthIndicator/LengthEditorPopover.tsx
new file mode 100644
index 0000000..f06ff99
--- /dev/null
+++ b/theatre/studio/src/panels/SequenceEditorPanel/DopeSheet/Right/LengthIndicator/LengthEditorPopover.tsx
@@ -0,0 +1,96 @@
+import type {Pointer} from '@theatre/dataverse'
+import React, {useLayoutEffect, useMemo, useRef} from 'react'
+import styled from 'styled-components'
+import type {SequenceEditorPanelLayout} from '@theatre/studio/panels/SequenceEditorPanel/layout/layout'
+import {usePrism, useVal} from '@theatre/dataverse-react'
+import getStudio from '@theatre/studio/getStudio'
+import BasicNumberInput from '@theatre/studio/uiComponents/form/BasicNumberInput'
+import type {CommitOrDiscard} from '@theatre/studio/StudioStore/StudioStore'
+import {propNameText} from '@theatre/studio/panels/ObjectEditorPanel/propEditors/utils/SingleRowPropEditor'
+
+const greaterThanZero = (v: number) => isFinite(v) && v > 0
+
+const Container = styled.div`
+  display: flex;
+  gap: 8px;
+  padding: 4px 8px;
+  height: 28px;
+  align-items: center;
+`
+
+const Label = styled.div`
+  ${propNameText};
+  white-space: nowrap;
+`
+
+const LengthEditorPopover: React.FC<{
+  layoutP: Pointer<SequenceEditorPanelLayout>
+  /**
+   * Called when user hits enter/escape
+   */
+  onRequestClose: () => void
+}> = ({layoutP, onRequestClose}) => {
+  const sheet = useVal(layoutP.sheet)
+
+  const fns = useMemo(() => {
+    let tempTransaction: CommitOrDiscard | undefined
+
+    return {
+      temporarilySetValue(newLength: number): void {
+        if (tempTransaction) {
+          tempTransaction.discard()
+          tempTransaction = undefined
+        }
+        tempTransaction = getStudio()!.tempTransaction(({stateEditors}) => {
+          stateEditors.coreByProject.historic.sheetsById.sequence.setLength({
+            ...sheet.address,
+            length: newLength,
+          })
+        })
+      },
+      discardTemporaryValue(): void {
+        if (tempTransaction) {
+          tempTransaction.discard()
+          tempTransaction = undefined
+        }
+      },
+      permenantlySetValue(newLength: number): void {
+        if (tempTransaction) {
+          tempTransaction.discard()
+          tempTransaction = undefined
+        }
+        getStudio()!.transaction(({stateEditors}) => {
+          stateEditors.coreByProject.historic.sheetsById.sequence.setLength({
+            ...sheet.address,
+            length: newLength,
+          })
+        })
+      },
+    }
+  }, [layoutP, sheet])
+
+  const inputRef = useRef<HTMLInputElement>(null)
+  useLayoutEffect(() => {
+    inputRef.current!.focus()
+  }, [])
+
+  return usePrism(() => {
+    const sequence = sheet.getSequence()
+    const sequenceLength = sequence.length
+
+    return (
+      <Container>
+        <Label>Sequence length</Label>
+        <BasicNumberInput
+          value={sequenceLength}
+          {...fns}
+          isValid={greaterThanZero}
+          inputRef={inputRef}
+          onBlur={onRequestClose}
+        />
+      </Container>
+    )
+  }, [sheet, fns, inputRef])
+}
+
+export default LengthEditorPopover
diff --git a/theatre/studio/src/panels/SequenceEditorPanel/DopeSheet/Right/LengthIndicator.tsx b/theatre/studio/src/panels/SequenceEditorPanel/DopeSheet/Right/LengthIndicator/LengthIndicator.tsx
similarity index 96%
rename from theatre/studio/src/panels/SequenceEditorPanel/DopeSheet/Right/LengthIndicator.tsx
rename to theatre/studio/src/panels/SequenceEditorPanel/DopeSheet/Right/LengthIndicator/LengthIndicator.tsx
index 0a334b4..869d51f 100644
--- a/theatre/studio/src/panels/SequenceEditorPanel/DopeSheet/Right/LengthIndicator.tsx
+++ b/theatre/studio/src/panels/SequenceEditorPanel/DopeSheet/Right/LengthIndicator/LengthIndicator.tsx
@@ -17,6 +17,7 @@ import {
   useLockFrameStampPosition,
 } from '@theatre/studio/panels/SequenceEditorPanel/FrameStampPositionProvider'
 import {GoChevronLeft, GoChevronRight} from 'react-icons/all'
+import LengthEditorPopover from './LengthEditorPopover'
 
 const coverWidth = 1000
 
@@ -130,9 +131,13 @@ type IProps = {
 const LengthIndicator: React.FC<IProps> = ({layoutP}) => {
   const [nodeRef, node] = useRefAndState<HTMLDivElement | null>(null)
   const [isDraggingD] = useDragBulge(node, {layoutP})
-  const [popoverNode, openPopover, _, isPopoverOpen] = usePopover(() => {
-    return <div>poppio</div>
-  })
+  const [popoverNode, openPopover, closePopover, isPopoverOpen] = usePopover(
+    () => {
+      return (
+        <LengthEditorPopover layoutP={layoutP} onRequestClose={closePopover} />
+      )
+    },
+  )
 
   return usePrism(() => {
     const sheet = val(layoutP.sheet)
diff --git a/theatre/studio/src/panels/SequenceEditorPanel/RightOverlay/RightOverlay.tsx b/theatre/studio/src/panels/SequenceEditorPanel/RightOverlay/RightOverlay.tsx
index 72248a7..eafc0cb 100644
--- a/theatre/studio/src/panels/SequenceEditorPanel/RightOverlay/RightOverlay.tsx
+++ b/theatre/studio/src/panels/SequenceEditorPanel/RightOverlay/RightOverlay.tsx
@@ -5,7 +5,7 @@ import type {Pointer} from '@theatre/dataverse'
 import {val} from '@theatre/dataverse'
 import React from 'react'
 import styled from 'styled-components'
-import LengthIndicator from '@theatre/studio/panels/SequenceEditorPanel/DopeSheet/Right/LengthIndicator'
+import LengthIndicator from '@theatre/studio/panels/SequenceEditorPanel/DopeSheet/Right/LengthIndicator/LengthIndicator'
 import FrameStamp from './FrameStamp'
 import HorizontalScrollbar from './HorizontalScrollbar'
 import Playhead from './Playhead'
diff --git a/theatre/studio/src/store/stateEditors.ts b/theatre/studio/src/store/stateEditors.ts
index 51909a4..9807157 100644
--- a/theatre/studio/src/store/stateEditors.ts
+++ b/theatre/studio/src/store/stateEditors.ts
@@ -392,7 +392,7 @@ namespace stateEditors {
           export function setLength(
             p: WithoutSheetInstance<SheetAddress> & {length: number},
           ) {
-            _ensure(p).length = p.length
+            _ensure(p).length = parseFloat(p.length.toFixed(2))
           }
 
           function _ensureTracksOfObject(
diff --git a/theatre/studio/src/uiComponents/Popover/Popover.tsx b/theatre/studio/src/uiComponents/Popover/Popover.tsx
index b6e6e51..afa34c9 100644
--- a/theatre/studio/src/uiComponents/Popover/Popover.tsx
+++ b/theatre/studio/src/uiComponents/Popover/Popover.tsx
@@ -6,8 +6,6 @@ import {createPortal} from 'react-dom'
 import useWindowSize from 'react-use/esm/useWindowSize'
 import styled from 'styled-components'
 
-const minWidth = 190
-
 /**
  * How far from the menu should the pointer travel to auto close the menu
  */
@@ -15,14 +13,11 @@ const defaultPointerDistanceThreshold = 200
 
 const Container = styled.ul`
   position: absolute;
-  min-width: ${minWidth}px;
   z-index: 10000;
   background: ${transparentize(0.2, '#111')};
   color: white;
-  list-style-type: none;
-  padding: 2px 0;
+  padding: 0;
   margin: 0;
-  border-radius: 1px;
   cursor: default;
   pointer-events: all;
   border-radius: 3px;
diff --git a/theatre/studio/src/uiComponents/form/BasicNumberInput.tsx b/theatre/studio/src/uiComponents/form/BasicNumberInput.tsx
index 2cf4b4a..d9a902c 100644
--- a/theatre/studio/src/uiComponents/form/BasicNumberInput.tsx
+++ b/theatre/studio/src/uiComponents/form/BasicNumberInput.tsx
@@ -1,9 +1,11 @@
 import {theme} from '@theatre/studio/css'
 import {clamp, isInteger, round} from 'lodash-es'
 import {darken, lighten} from 'polished'
+import type {MutableRefObject} from 'react'
 import React, {useMemo, useRef, useState} from 'react'
 import styled from 'styled-components'
 import DraggableArea from '@theatre/studio/uiComponents/DraggableArea'
+import mergeRefs from 'react-merge-refs'
 
 type IMode = IState['mode']
 
@@ -75,9 +77,8 @@ const FillIndicator = styled.div`
   }
 `
 
-function isValueAcceptable(s: string) {
-  const v = parseFloat(s)
-  return !isNaN(v)
+function isFiniteFloat(s: string) {
+  return isFinite(parseFloat(s))
 }
 
 type IState_NoFocus = {
@@ -98,6 +99,8 @@ type IState_Dragging = {
 
 type IState = IState_NoFocus | IState_EditingViaKeyboard | IState_Dragging
 
+const alwaysValid = (v: number) => true
+
 const BasicNumberInput: React.FC<{
   value: number
   temporarilySetValue: (v: number) => void
@@ -105,13 +108,22 @@ const BasicNumberInput: React.FC<{
   permenantlySetValue: (v: number) => void
   className?: string
   range?: [min: number, max: number]
+  isValid?: (v: number) => boolean
+  inputRef?: MutableRefObject<HTMLInputElement | null>
+  /**
+   * Called when the user hits Enter. One of the *SetValue() callbacks will be called
+   * before this, so use this for UI purposes such as closing a popover.
+   */
+  onBlur?: () => void
 }> = (propsA) => {
   const [stateA, setState] = useState<IState>({mode: 'noFocus'})
+  const isValid = propsA.isValid ?? alwaysValid
 
   const refs = useRef({state: stateA, props: propsA})
   refs.current = {state: stateA, props: propsA}
 
   const inputRef = useRef<HTMLInputElement | null>(null)
+
   const bodyCursorBeforeDrag = useRef<string | null>(null)
 
   const callbacks = useMemo(() => {
@@ -122,9 +134,9 @@ const BasicNumberInput: React.FC<{
 
       setState({...curState, currentEditedValueInString: value})
 
-      if (!isValueAcceptable(value)) return
-
       const valInFloat = parseFloat(value)
+      if (!isFinite(valInFloat) || !isValid(valInFloat)) return
+
       refs.current.props.temporarilySetValue(valInFloat)
     }
 
@@ -132,16 +144,17 @@ const BasicNumberInput: React.FC<{
       if (refs.current.state.mode === 'editingViaKeyboard') {
         commitKeyboardInput()
         setState({mode: 'noFocus'})
-      } else {
       }
+      if (propsA.onBlur) propsA.onBlur()
     }
 
     const commitKeyboardInput = () => {
       const curState = refs.current.state as IState_EditingViaKeyboard
-      if (!isValueAcceptable(curState.currentEditedValueInString)) {
+      const value = parseFloat(curState.currentEditedValueInString)
+
+      if (!isFinite(value) || !isValid(value)) {
         refs.current.props.discardTemporaryValue()
       } else {
-        const value = parseFloat(curState.currentEditedValueInString)
         if (curState.valueBeforeEditing === value) {
           refs.current.props.discardTemporaryValue()
         } else {
@@ -256,6 +269,9 @@ const BasicNumberInput: React.FC<{
     value = 'NaN'
   }
 
+  const _refs = [inputRef]
+  if (propsA.inputRef) _refs.push(propsA.inputRef)
+
   const theInput = (
     <Input
       key="input"
@@ -266,7 +282,7 @@ const BasicNumberInput: React.FC<{
       onKeyDown={callbacks.onInputKeyDown}
       onClick={callbacks.onClick}
       onFocus={callbacks.onFocus}
-      ref={inputRef}
+      ref={mergeRefs(_refs)}
       onMouseDown={(e: React.MouseEvent) => {
         e.stopPropagation()
       }}
diff --git a/yarn.lock b/yarn.lock
index 2025759..b5f7a76 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -16436,6 +16436,7 @@ fsevents@^1.2.7:
     react-error-boundary: ^3.1.3
     react-icons: ^4.2.0
     react-is: ^17.0.2
+    react-merge-refs: ^1.1.0
     react-shadow: ^19.0.2
     react-use: ^17.2.4
     react-use-gesture: ^9.1.3