Table cell misalignment and table getting wider when moving the mouse over it with flex layout

Describe your context
Here's my setup:

python --version
Python 3.7.5

conda list dash
# Name                    Version
dash                      1.4.1
dash-core-components      1.3.1
dash-html-components      1.0.1
dash-renderer             1.1.2
dash-table                4.4.1

• OS: Windows 7
• Browsers:
  • Chrome 77.0.3865.75
  • IE 11.0.9600.19504

Describe the bug
Consider there following piece of code:

import os

import dash
import dash_html_components as html
import dash_table
import pandas as pd

df = pd.read_csv('https://raw.githubusercontent.com/plotly/datasets/master/solar.csv')

app = dash.Dash(__name__)

app.layout = html.Div(
    children=[
        dash_table.DataTable(
            id='table',
            columns=[{'name': c, 'id': c} for c in df.columns],
            fixed_rows=dict(headers=True, data=0),
            data=df.to_dict('records')
        )
    ],
    className='eight columns',
    style={'display': 'flex', 'justify-content': 'center'})

if __name__ == '__main__':
    app.run_server(debug=True)

Now we have two problems:

1. The browser renders the table with a misalignment between header and the rest of the table, see screenshots below
2. When I start moving my mouse over the table then every time the mouse pointer crosses any of the cell boundaries then the table gets a few pixels wider (in Chrome) or smaller (in IE), see screenshots below.

Expected behavior

1. There should be no misalignment between header and the rest of the table
2. The mouse moving over the table should have no effect whatsoever.

Screenshots
Initial state in Chrome:

After having moved the mouse over the table for a bit:

Initial state in IE:

After having moved the mouse over the table for a bit:

使用提供的 Python Dash DataTable 示例，采用 flex 布局和固定表头行重现该问题。在 Chrome 和 IE 中将指针移过单元格边界时，检查表头/表体对齐情况和表格宽度。完成的标准是表头保持对齐，并且鼠标移动不再改变表格宽度。