How to make Wealth-Lab to treat all symbols as stocks and buy or sell at limit with 4 decimal places, $5.2562 as an example?

1. Preferences > Advanced Options > Decimal Places
2. "Disable futures mode" in Symbol Info Manager

P.S. When version 6.2 comes (June), there's going to be an important change here.

First, you'll have the option to turn off stop/limit rounding entirely. This makes Wealth-Lab backtest with full precision Stop/Limit orders.

Second, there will be a change in how Wealth-Lab applies rounding to tick boundary to Stop/Limit prices. There's a known issue with taking Stop/Limit orders when they fall at the extreme price of a bar (i.e. at the High/Low), so the change is going to be beneficial here.

This may be the same as what Eugene described as "Second", but just to clarify...

In 6.2, the Decimal Places that you configure in Advanced Options will also become the "tick boundary" for stocks. So, if you enter 4 decimals, stocks will be displayed and traded at 4 decimals.