when a container is put on a slide (usually by using layouts) it has a helper 
text that says "click here to insert title", " doubleclick to insert graphics".

there are background colours when text doesn't change it's colour together :

create a new presentation, choose master page "recommendation of a strategy"
choose layout "Title, Chart" - notice text in the chart area.

all other helper texts have turned white, the one for chart stays black.

this is true for colours sun1, bordeaux (title etc changes to white, chart, 
spreadsheet, clipart - stays black), probably others.

the same effect can be seen also by simply changing background colour to one of 
mentioned above.