To locate hidden rows and columns, you can have following approaches –
1. Locate them manually. Hence, if after row 4, row 6 comes,row 5 is hidden.
2. ALT+EGSY and Enter. It will select all visible cells and it will mark hidden rows and columns with highlight. But on a white background, it may be difficult to judge this highlight. To overcome this, CTRL+A to select complete sheet and fill in a dark colour on the entire sheet and do ALT+EGSY and Enter. Now, you can make out hidden rows and columns. Don't forget to return back to white background after locating hidden rows and columns.
In below Column D and row 5 are hidden. See, it is difficult to make out highlighted column D and row 5.
On a dark background, see column D and row 5 can be clearly made out by dark lines.
