A family of Microsoft word processing software products for creating web, email, and print documents.
I find that the problem is not clicking into the rich text content control, but using the tab key to get out of it. This is due to what I'd consider a design fault by Microsoft: Pressing the tab key in a rich text control inserts a tab character, instead of jumping to the next content control as for all other types of content control. This is also contrary to the behavior of the tab key in a table without content controls, where the tab key jumps to the next cell, and Ctrl+Tab is required to insert a tab character.
Putting a rich text content control inside a table compounds that fault. Now pressing the tab key inside the rich text content control inexplicably does not insert a tab character, but the Tab key press is passed to the table, so the cursor moves to the next cell. For your example, if the rich text control is in column 2 of the row labeled Colour, tabbing out of the control moves the cursor to the Size label cell. Note that this occurs even when there is no repeating section content control in the table, and no bounding box around the table, so it isn't the fault of the repeating control.
Correcting this behavior would take revision of the programming of the rich text content control by Microsoft.