QTextEdit takes longer and longer to draw text

I am using a QTextEdit, and I update the text with a call to sethtml(Qstring);

the text is a simple tables that changes every second. Initially the setHtml method is fast (0 ms); but after time (depending on rate) it takes longer for setHTML to return.

I am calling sethtml at 1Hz rate. After 12 hours it takes over 350 ms to call sethtml

This increase continues the longer the program runs.

I created a simple test program that show this my test project; at 100 hz the problem  shows in about 5-10 minutes. at 10 hz it takes a 30-60 minutes, and at 1 hz 10 hours or so.

I want my application to run for days, I this is causing a major issue.

I did not have this issue while running Qt 4.8.7