Dracula At Night Theme extension doesn't work

[rayakoren]

Bug Description:

Dracula At Night theme appears to be light and transparent, making it hard to read the menu commands because the text overlaps.

Steps to Reproduce:

1. Install Dracula At Night extension from Open VSX Registry.
2. Click File -> Settings -> Color Theme -> Dracula At Night
3. Open any menu (for example: 'Selection')

Additional Information

• Operating System: mac OS 11.0.1
• Theia Version: 1.22.5

Error stacktrace:
TypeError: Cannot read property 'length' of null
at Object.parseHex (http://localhost:3000/vs/editor/editor.main.js:1305:38)
at Function.Color.fromHex (http://localhost:3000/vs/editor/editor.main.js:1072:37)
at StandaloneTheme.getColors (http://localhost:3000/vs/editor/editor.main.js:127144:50)
at StandaloneTheme.getColor (http://localhost:3000/vs/editor/editor.main.js:127159:30)
at DecorationCSSRules.resolveValue (http://localhost:3000/vs/editor/editor.main.js:102921:41)
at DecorationCSSRules.collectCSSText (http://localhost:3000/vs/editor/editor.main.js:102911:34)
at DecorationCSSRules.getCSSTextForModelDecorationClassName (http://localhost:3000/vs/editor/editor.main.js:102840:18)
at DecorationCSSRules._buildCSS (http://localhost:3000/vs/editor/editor.main.js:102786:40)
at new DecorationCSSRules (http://localhost:3000/vs/editor/editor.main.js:102738:18)
at createCSSRules (http://localhost:3000/vs/editor/editor.main.js:102637:29)

[vince-fugnitto]

Closing in favor of #8536.