message: Select apropriate theme colour for popover.
diff: @@ -350,6 +350,11 @@ export default class MessageComposer extends React.Component {
  </div>;
  }
  + // Fall back to default highlight color if we can't compute one from the DOM
  + const highlightColor = document.getElementById('mx_theme_accentColor') ?
  + window.getComputedStyle(document.getElementById('mx_theme_accentColor')).color :
  + '#76CFA6';
  +
  const stickers = <Popover
  isOpen={this.state.showStickers}
  position={'top'}
  @@ -360,13 +365,13 @@ export default class MessageComposer extends React.Component {
  position={position}
  targetRect={targetRect}
  popoverRect={popoverRect}
  - arrowColor={'#76CFA6'}
  + arrowColor={highlightColor}
  arrowSize={20}
  >
  <div
  className='mx_PopoverOuterContainer'
  style={{
  - border: '1px solid #76CFA6',
  + border: `1px solid ${highlightColor}`,
  }}
  >
  { this.state.stickersContent }
  