I have noticed a number of seemingly related intermittent problems in an Excel 2010 workbook.
1. Despite best efforts, a textbox in a userform set to "showmodal=false" will not take the caret on first opening. It WILL if modal.
2. Occasionally, a commandbutton set to be the default will not operate with 'Enter' but needs to be clicked.
3. Occasionally, the same textbox, although set correctly to move to the next control with TAB, places a TAB in that textbox instead.
4. When a userform is selected in design mode, the wrong userform is displayed, the correct one only appearing when clicked again.
These problems, although I cannot be assured that they are connected, have presented in the same time period.
They soon are restored to normal with the use of other controls, and the problems do not appear again during that period of use.

Points that may be of interest are (A) that my userform was made by copying and pasting controls from another workbook into a blank userform in the present workbook to save time. (B) All of the controls in question are themselves located within a frame.

I have a reasonably good understanding of general VBA so I suspect it is not something that is overly obvious. In any case, perhaps parts of the problems will seem familiar to others.

Any ideas, folks?