Commented Unassigned: PropertyGrid.Update() slowing down each time called [22310]

I needed to refresh object values in grid frequently and fast, so I was using property grid's Update method.

However, I have noticed that this becomes slower and slower each time the method is called. For example, this code simulates gradual slow down:

// Assign selected object
PGMain.SelectedObject = MyObject;

// Takes 618 ms
for (var x = 0; x < 100; x++) PGMain.Update();

// Takes 1649 ms
for (var x = 0; x < 100; x++) PGMain.Update();

// Takes 2739 ms
for (var x = 0; x < 100; x++) PGMain.Update();

// Takes 3730 ms
for (var x = 0; x < 100; x++) PGMain.Update();

Has this bug been noticed before?
Are there any resolutions to this issue?
Comments: ** Comment from web user: dusansmail **

Note that I am using Extended WPF Toolkit™ Community Edition 2.9 in VS project.
The commercial Xceed Wpf Toolkit Plus does not have this issue.