This regression is similar to
and CORE-14144 . The left-sided cursor, which is displayed in some apps like MS Office and Net Framework installer, is too large and has a bold black border. This cursor appears since r75896, after syncing riched20 with Wine-Staging 2.16 (commit ec29185ee5cc8fb28fbcf81c5ce36483bc25992e) in the past year. In r75895 is the classic win2k3-styled cursor, which fits into the ReactOS classic style also. CORE-14608
For reproducing this, for example, just launch Net Framework 2.0 SP2 installer and move the mouse to the left side of license agreement dialog and place it on the border.