[BUG] Vertically aligned panel in live alternative screen stretches vertically over entire screen

[Dr-ZeeD]

Describe the bug
When I try to vertically center a panel within the alternate screen mode of the live mode, it instead stretches over the entire screen with the text being aligned on top of the panel.

To Reproduce
Minimal code:

from time import sleep

from rich.align import Align
from rich.panel import Panel
from rich.live import Live
from rich import print

align = Align.center(
    Panel("Text", padding=(1, 2)),
    vertical="middle",
    height=20
)

with Live(align, screen=True):
    while True:
        sleep(0.4)

Platform
macOS 11 with iTerm2 Build 3.4.4

Diagnose
Command:

python -m rich.diagnose

Result:

╭────────────────── <class 'rich.console.Console'> ───────────────────╮
│ A high level console interface.                                     │
│                                                                     │
│ ╭─────────────────────────────────────────────────────────────────╮ │
│ │ <console width=71 ColorSystem.TRUECOLOR>                        │ │
│ ╰─────────────────────────────────────────────────────────────────╯ │
│                                                                     │
│     color_system = 'truecolor'                                      │
│         encoding = 'utf-8'                                          │
│             file = <_io.TextIOWrapper name='<stdout>' mode='w'      │
│                    encoding='utf-8'>                                │
│           height = 71                                               │
│ is_dumb_terminal = False                                            │
│   is_interactive = True                                             │
│       is_jupyter = False                                            │
│      is_terminal = True                                             │
│   legacy_windows = False                                            │
│         no_color = False                                            │
│          options = ConsoleOptions(size=ConsoleDimensions(width=71,  │
│                    height=71), legacy_windows=False, min_width=1,   │
│                    max_width=71, is_terminal=True,                  │
│                    encoding='utf-8', justify=None, overflow=None,   │
│                    no_wrap=False, highlight=None, height=None)      │
│            quiet = False                                            │
│           record = False                                            │
│         safe_box = True                                             │
│             size = ConsoleDimensions(width=71, height=71)           │
│        soft_wrap = False                                            │
│           stderr = False                                            │
│            style = None                                             │
│         tab_size = 8                                                │
│            width = 71                                               │
╰─────────────────────────────────────────────────────────────────────╯

Command:

python -m rich._windows

Result:

platform="Darwin"
WindowsConsoleFeatures(vt=False, truecolor=False)

Command:

pip freeze | grep rich

Result:

rich==9.11.1

[willmcgugan]

Please try 9.12.0

[Dr-ZeeD]

Now that's embarrassing 😅 works like a charm, thank you so much!