Kile Version 2.9.60 Using KDE Development Platform 4.8.2 (4.8.2)
Kate Version 3.8.2 Using KDE Development Platform 4.8.2 (4.8.2)

When dynamic word wrap is activated, the source text sometimes behaves unexpected:

1. When dragging the scroll bar
2. When starting to type while a wrapped line is not shown completely

Reproducible: Always

Steps to Reproduce:
1. Create a document, activate dynamic word wrap (F10) and create/paste several lines that are wrapped several times. Make sure the text is long enough so that the vertical scroll bar appears.
2. Drag the vertical scrollbar up and down slowly. Multiple wrapped lines appear/disappear as one element.
3. Use mousewheele to move up and down. Multilines can be positioned in the middle.
4. Use the small up/down buttons below the vertical scroll bar. Multilines can be positioned in the middle.
5. Position the text using mouswheele, so that a multiline is positioned in the middle.
6. Place the cursor anywhere and start typing. The half-shown multiline jumps down so the beginning of the line is visible.
Actual Results:  
Unexpected jumping of the sourcetext

Expected Results:  
Scrolling should be always smooth, no expected jumps. 

This behavior makes it very difficult navigating in a text with many wrapped lines.