Intellij idea programming 1. Black thick lines or black cursor 2. A solution that cannot wrap a line by carriage return. (Practical Recommendation Method 2)

reason: it is usually caused by accidentally pressing insert. Some computers abbreviate insert, putting Del and Ins together, and Ins is the insert key.
Method 1. Click Intellij Idea on the upper left corner of the main interface, File> Settings> The diagram below * * * *
Put him on the Use block caret, and you can get back to your old self. ***

Method 2 (recommended) : Press and hold the Fn+ INSERT key to restore directly.
note: do not press Fn+insert if Use block caret is checked, otherwise the enter key will fail to wrap.
PS: restore the enter enter key newline function solution:
cancel Use block caret in the check box (default is no check, no change can be ignored), and then hold down Fn+insert key, so that the cursor and return will return to the original.