I recently had a very strange issue develop seemingly out of the blue with a long-time file I use to upload listings to Ebay for my business. Specifically, after editing any cells within a particular worksheet, blank or otherwise, significant lag was produced only when scrolling up or down on the page, and this lag would continue until a manual calculation was performed on the worksheet (ie, I have calculations set to manual in Options).

After much testing and having striped down my affected worksheets layer by layer I discovered that the issue was caused by something rather strange: the use of multiple font colors in a "Description" field whose cells contain HTML-based text (I had made altered the font color of a small portion of text within this field a few weeks back as a way of making it easier to identify needed changes when preparing specific listings). In particular, when any cell is changed within a worksheet while the "Description" field is visible on the page, scrolling upwards or downwards through these offending cells would produce the aforementioned lag. It was a puzzling revelation to say the least.

Is this some sort of known issue within Excel? If not, what are my options for avoiding this type of issue in the future? While I would prefer to continue utilizing multiple font colors moving forward, if there would be no viable solution to this issue I will simply go back to utilizing a single font color.