This looks like a regression in katepart that is included with KDE 4.9 beta1.

I edit lots of xml files in different editors that as far as I know are all based on the katepart component (Kate, Kwrite, Krusader).

The contents look like (all in one line - lots of line like this):

<prescriptionDrugs AppID="W54317002/P50851" pos="1" copaymentListType="B" copaymentPercent="90" diseaseCode="458" drugCode="W54317002" quantity="90" retailPrice="2.793666" refPrice="2.514299" retailValue="251.43" copaymentValue="226.29" copaymentValue50="125.71" copaymentValue40="100.58" byProtocol="0" diagnosticType="2" vatPercent="9" protocolValue="0" quantityPerPackage="30" pricePerPackage="83.81000" personValue="23.38307" drugInvoiceNo="CT AMB-1118" drugInvoiceDate="2012-06-01"/>

I jump with the cursor using Ctrl+Arrow Left or Right.

if the file contains more than 1000 lines the jumping is very slow but only when reaching the " (quotation mark) character. That is - when jumping to a =, /, - character the speed is OK but when it reaches the " the cursor stops for what feels like 1 second before jumping to the next stop.

The speed feels almost ok with files of around 500 lines and is instant with files of 200 lines.

Reproducible: Always

Steps to Reproduce:
1. Edit large xml file with Kate (more than 1000 lines)
2. Use Ctrl+Arrow to jump with cursor left or right inside a line
3. The jumping is slow around the " (quotation mark) character.