Problem with \label and \ref in TeXMaker?

Question

TeX

Hey Habr. There was the following problem: when using \label and \ref in TexMaker, when compiling, a rectangle appears containing the name of the label. Below is the code and the result of the output of what happened. So the question is - how to get rid of this rectangle?

\begin{center}<br/>
\begin{figure}[h]<br/>
\centering{}\includegraphics[width=0.75\textwidth]{img/2}\caption{Чебышевские характеристики затухания с пульсациями 1 дБ.}<br/>
\label{fig:4eb1}<br/>
\end{figure}<br/>
\end{center}<br/>
$\frac{w}{w_1}-1=4$ $4\leqslant n\leqslant3$, следовательно<br/>
порядок фильтра n = 4. Используя Чебышевские характеристики затухания с пульсациями (рис. \ref{fig:4eb1}),можно определить число резонаторов фильтра.<br/>

Answer 1

\begin{center}\begin{figure} is not correct because float is a floating object. \begin{figure}\centering...

Answer 2

Found the cause of the trouble in the preamble was
\usepackage{showkeys}