Fix loading of Scenario tab

[ekatef]

Scenario Comparison at first do not show text elements (the diagram legend and the table) and requires refreshing to be displayed properly.

[ekatef]

The issue is caused by a conflict with the dark theme. Possible (standard) solutions:

• change the font colour to be visible under both themes;
• check the current theme and adjust the font colour to match it.

[ekatef]

Fixed with #663aac14f524f33b1f54c75c0c3de7973e9456d7

[ekatef]

Closed as fixed by defining elements colour with a web-safe grey.