fix row selection alignment

CHANGELOG.md

@@ -9,7 +9,10 @@ This project adheres to [Semantic Versioning](http://semver.org/).
 
 [#567](https://github.com/plotly/dash-table/issues/567)
 - Add support for missing `border-radius` in style_** props
-- Fix table's inner vs. outer container styling 
+- Fix table's inner vs. outer container styling
+
+[#18](https://github.com/plotly/dash-table/issues/18)
+- Fix row selection vertical and horizontal alignment
 
 ## [4.2.0] - 2019-08-27
 ### Added

src/dash-table/derived/cell/operations.tsx

@@ -37,10 +37,11 @@ function rowSelectCell(idx: number, rowSelectable: Selection, selectedRows: numb
     return (<td
         key='select'
         className='dash-select-cell'
-        style={{ width: `30px`, maxWidth: `30px`, minWidth: `30px` }}
+        style={{ width: `30px`, maxWidth: `30px`, minWidth: `30px`, textAlign: 'center' }}
     >
         <input
             type={rowSelectable === 'single' ? 'radio' : 'checkbox'}
+            style={{ verticalAlign: 'middle' }}
             name='row-select'
             checked={R.contains(idx, selectedRows)}
             onChange={() => {