_UITextContainerView's frame issue

[ghost]

If I set maxNumberOfLines = 3, press return key on keyboard after line number grows to 2 will cause textview's _UITextContainerView frame issue.

for example, HPTextViewInternal's frame is {0,0,100,50} when I have two lines, it changes to {0,0,100,60} when I have three lines, but _UITextContainerView's frame is still {0,0,100,50}, it causes the UI issue. It looks like this:

I look into the code, find that when this case happens, - (void)drawRect:(CGRect)rect of HPTextViewInternal will receive a rect's y point which has a negative value such -10,

After I change

if (newSizeH <= maxHeight)

in - (void)refreshHeight which in HPGrowingTextView.m to

if (newSizeH < maxHeight)

the precent of this case chance change from 100% to 10%,
Anyone can help? Please forgive my poor description.